The Fenton-like reaction between Cu^(2+)and H_(2)O_(2)was employed in chemical mechanical polishing to achieve efficient and high-quality processing of tungsten.The microstructure evolution and material removal rate o...The Fenton-like reaction between Cu^(2+)and H_(2)O_(2)was employed in chemical mechanical polishing to achieve efficient and high-quality processing of tungsten.The microstructure evolution and material removal rate of tungsten during polishing process were investigated via scanning electron microscopy,X-ray photoelectron spectroscopy,ultraviolet−visible spectrophotometry,and electrochemical experiments.The passivation behavior and material removal mechanism were discussed.Results show that the use of mixed H_(2)O_(2)+Cu(NO_(3))_(2)oxidant can achieve higher polishing efficiency and surface quality compared with the single oxidant Cu(NO_(3))_(2)or H_(2)O_(2).The increase in material removal rate is attributed to the rapid oxidation of W into WO_(3)via the chemical reaction between the substrate and hydroxyl radicals produced by the Fenton-like reaction.In addition,material removal rate and static etch rate exhibit significantly different dependencies on the concentration of Cu(NO_(3))_(2),while the superior oxidant for achieving the balance between polishing efficiency and surface quality is 0.5 wt.%H_(2)O_(2)+1.0 wt.%Cu(NO_(3))_(2).展开更多
CeO_(2)is increasingly recognized as a viable polishing abrasive for SiO_(2)-based substrates,such as K9 glass,leveraging its intrinsic chemical mechanical polishing property.Although LaOF can improve the performance ...CeO_(2)is increasingly recognized as a viable polishing abrasive for SiO_(2)-based substrates,such as K9 glass,leveraging its intrinsic chemical mechanical polishing property.Although LaOF can improve the performance of CeO_(2)abrasive,the specific mechanism underlying this enhancement remains elusive.Herein,LaOF-CeO_(2)composite abrasive was prepared by co-precipitation method,aiming to elaborate on the influence of LaOF on the abrasive's polishing efficiency.It is found that the integration of LaOF results in the formation of LaOF-CeO_(2)composite characterized by a remarkably reduced primary particle size of approximately 41 nm,which primarily accounts for the improvement in polishing performance.Furthermore,the increasement in Ce^(3+)content and the Zeta potential both contribute to the superior function of the composite abrasive.Notably,the synergistic effect of these parameters is manifested in an elevated material removal rate reaching 1091.197 nm/min,coupled with a minimized surface roughness of as low as 0.546 nm when applied to K9 glass surface.The findings of this work offer novel insights into the role of LaOF in facilitating the performance of Ce-based abrasives,potentially influencing future advancements in the field of precision surface processing.展开更多
Rare earth carbonates are essential precursors for the synthesis of oxide materials.In this study,we utilized in situ monitoring equipment to explore the alterations in the crystallization during the coprecipitation s...Rare earth carbonates are essential precursors for the synthesis of oxide materials.In this study,we utilized in situ monitoring equipment to explore the alterations in the crystallization during the coprecipitation synthesis of cerium carbonate.By controlling the crystallization pathway and in the absence of any te mplating agents,we successfully synthesized a unique sphe rical self-assembled cerium oxide particle(Ceria-S).The Ceria-S exhibits excellent polishing performance.The crystallization process of cerium carbonate at 50℃persists for roughly 50 min.During the initial stages of crystallization from 0 to t_(3),the precipitated particles are amorphous.This is followed by a plateau phase of crystal growth from t_(3)to t_(5).Subsequently,during the burst crystallization phase from t_(5)to t_(6),Ce_(2)(CO_(3))_(3)·6H_(2)O and Ce_(2)O(CO_(3))_(2)·nH2O are formed,exhibiting a rod-like crystal morphology.By rapidly drying the precipitated particles at 60℃for 10 min and calcining,Ceria-S is obtained.The Ceria-S,with an average diameter of 180 nm,is assembled from primary cerium oxide nanoparticles of approximately 15 nm.Owing to the self-assembly structure of cerium oxide spherical nanoparticles,they exhibit a significantly larger specific surface area,resulting in an elevated concentration of Ce^(3+)as high as 35.5%.The Ceria-S exhibits a polishing removal rate of 420 nm/min,effectively decreasing the surface roughness(S_(a))of K9 glass from 1.605 to 0.404 nm.展开更多
The lanthanum-cerium-based slurry(LC-slurry)is extensively utilized in the chemical mechanical polishing(CMP)of TFT-LCD glass substrates,optical lenses,and other glass products.Sodium hexametaphosphate(SHMP),as a disp...The lanthanum-cerium-based slurry(LC-slurry)is extensively utilized in the chemical mechanical polishing(CMP)of TFT-LCD glass substrates,optical lenses,and other glass products.Sodium hexametaphosphate(SHMP),as a dispersant,is commonly employed to enhance the dispersion properties of LCslurry for improved polishing performance.However,the tendency of sedimentation to form a compacted sediment layer,which is challenging to redisperse,increases storage difficulty and polishing equipment failure risk,thereby limiting its utilization in CMP.In the present study,sodium carboxymethylcellulose(CMC-Na),a long-chain organic polymer,was employed to enhance the redispersibility of LC-slurry containing SHMP.A comprehensive investigation was conducted on the influence of CMC-Na dosage and slurry pH on dispersibility,redispersibility and polishing performance.Additionally,an analysis was carried out to elucidate the underlying mechanism behind the effect of CMC-Na.The study demonstrates that the LC-slurry,containing 250 ppm SHMP and 500 ppm CMC-Na,exhibits excellent dispersibility and redispersibility.Further polishing tests demonstrate that compared to the LC-slurry containing only SHMP,utilizing the slurry containing both SHMP and CMC-Na at various pH for polishing thin film transistor liquid crystal display(TFT-LCD)glass substrates results in a reduction of both material removal rate(MRR)and surface roughness(Sa).Specifically,when adjusting the slurry to a pH range of 5-6,the MRR can reach up to 330 nm/min,which closely approximates the MRR achieved by LC-slurry containing only 250 ppm SHMP at corresponding pH values.Meanwhile,after polishing,the surface roughness of the glass substrate measures approximately 0.47 nm.展开更多
The textured roll and polished roll were applied instead of the ground roll in a 20-high mill to conduct two-pass rolling of 316L stainless steel strip with thickness of 0.027 mm.After the two-pass rolling with the te...The textured roll and polished roll were applied instead of the ground roll in a 20-high mill to conduct two-pass rolling of 316L stainless steel strip with thickness of 0.027 mm.After the two-pass rolling with the textured roll and polished roll(TPR),the surface roughness of the strip is dramatically reduced,and the surface topographical anisotropy index is diminished to 30.9%of the initial strip.Comparing with the strip rolled using the ground roll in both passes(GGR),the elongation of TPR rolled strip is obviously improved,and the mechanical property anisotropy is greatly weakened.The anisotropy index of tensile strength and elongation are 42.58%and 52.59%of that of GGR rolled strip,which is mainly attributed to the significant decrease of the texture intensity of the strip by TPR process.The results indicate that TPR process can obtain the stainless steel ultra-thin strip with smooth and uniform surface topography and good mechanical properties.展开更多
Atomic surfaces are strictly required by high-performance devices of diamond.Nevertheless,diamond is the hardest material in nature,leading to the low material removal rate(MRR)and high surface roughness during machin...Atomic surfaces are strictly required by high-performance devices of diamond.Nevertheless,diamond is the hardest material in nature,leading to the low material removal rate(MRR)and high surface roughness during machining.Noxious slurries are widely used in conventional chemical mechanical polishing(CMP),resulting in the possible pollution to the environment.Moreover,the traditional slurries normally contain more than four ingredients,causing difficulties to control the process and quality of CMP.To solve these challenges,a novel green CMP for single crystal diamond was developed,consisting of only hydrogen peroxide,diamond abrasive and Prussian blue(PB)/titania catalyst.After CMP,atomic surface is achieved with surface roughness Sa of 0.079 nm,and the MRR is 1168 nm·h^(-1).Thickness of damaged layer is merely 0.66 nm confirmed by transmission electron microscopy(TEM).X-ray photoelectron spectroscopy,electron paramagnetic resonance and TEM reveal that·OH radicals form under ultraviolet irradiation on PB/titania catalyst.The·OH radicals oxidize diamond,transforming it from monocrystalline to amorphous atomic structure,generating a soft amorphous layer.This contributes the high MRR and formation of atomic surface on diamond.The developed novel green CMP offers new insights to achieve atomic surface of diamond for potential use in their high-performance devices.展开更多
On March 19,CIIS President Chen Bo met with Wojciech Zajączkowski,Director of the Asia-Pacific Department of the Ministry of Foreign Affairs of Poland.CIIS Vice President Liu Feitao moderated a discussion with the del...On March 19,CIIS President Chen Bo met with Wojciech Zajączkowski,Director of the Asia-Pacific Department of the Ministry of Foreign Affairs of Poland.CIIS Vice President Liu Feitao moderated a discussion with the delegation led by Director Zajączkowski.The two sides exchanged in-depth views on the current China-Europe relations,China-Poland relations,and the Ukraine crisis.展开更多
It is a challenge to polish the interior surface of an additively manufactured component with complex structures and groove sizes less than 1 mm.Traditional polishing methods are disabled to polish the component,meanw...It is a challenge to polish the interior surface of an additively manufactured component with complex structures and groove sizes less than 1 mm.Traditional polishing methods are disabled to polish the component,meanwhile keeping the structure intact.To overcome this challenge,small-grooved components made of aluminum alloy with sizes less than 1 mm were fabricated by a custom-made printer.A novel approach to multi-phase jet(MPJ)polishing is proposed,utilizing a self-developed polisher that incorporates solid,liquid,and gas phases.In contrast,abrasive air jet(AAJ)polishing is recommended,employing a customized polisher that combines solid and gas phases.After jet polishing,surface roughness(Sa)on the interior surface of grooves decreases from pristine 8.596μm to 0.701μm and 0.336μm via AAJ polishing and MPJ polishing,respectively,and Sa reduces 92%and 96%,correspondingly.Furthermore,a formula defining the relationship between linear energy density and unit defect volume has been developed.The optimized parameters in additive manufacturing are that linear energy density varies from 0.135 J mm^(-1)to 0.22 J mm^(-1).The unit area defect volume achieved via the optimized parameters decreases to 1/12 of that achieved via non-optimized ones.Computational fluid dynamics simulation results reveal that material is removed by shear stress,and the alumina abrasives experience multiple collisions with the defects on the heat pipe groove,resulting in uniform material removal.This is in good agreement with the experimental results.The novel proposed setups,approach,and findings provide new insights into manufacturing complex-structured components,polishing the small-grooved structure,and keeping it unbroken.展开更多
Additive manufacturing(AM)is a reliable technique for constructing highly complex metallic parts.Direct energy deposition(DED)is one of the most common technologies used for AM-printed metal alloys.However,issues such...Additive manufacturing(AM)is a reliable technique for constructing highly complex metallic parts.Direct energy deposition(DED)is one of the most common technologies used for AM-printed metal alloys.However,issues such as weak binding,poor accuracy,and rough surfaces still affect the final products.These limitations in the metal-feed DED process indicate that post-processing techniques are required to achieve high quality in terms of both mechanical properties and surface finish.Conventional contact-based post-processing methods have several drawbacks,including difficulties in accessing complex shapes,environmental impact,high time consumption and cost,and health risks for operators.To address these problems and improve surface quality,a laser polishing process has been proposed.By melting or ablating the material with a laser,the laser-polishing process enables the smoothing of the initial topography.It should be noted that there are currently no reviews focusing specifically on laser polishing as a surface treatment technology for the DED process.Therefore,this review presents a unique examination of the mechanisms and primary user-set parameters for both continuous wave(CW)and pulsed laser polishing.The objective is to demonstrate the capabilities of each process and the benefits of using them for the surfaces of DED metal parts.Additionally,existing knowledge and technology gaps are identified,and future research directions are discussed.展开更多
Slicing and post-treatment of SiC crystals have been a significant challenge in the integrated circuit and microelectronics industry.To compete with wire-sawing and mechanical grinding technology,a promis-ing approach...Slicing and post-treatment of SiC crystals have been a significant challenge in the integrated circuit and microelectronics industry.To compete with wire-sawing and mechanical grinding technology,a promis-ing approach combining laser slicing and laser polishing technologies has been innovatively applied to increase utilization and decrease damage defects for single crystal 4H-SiC.Significant material utiliza-tion has been achieved in the hybrid laser processes,where material loss is reduced by 75%compared to that of conventional machining technologies.Without any special process control or additional treat-ment,an internally modified layer formed by laser slicing can easily separate the 4H-SiC crystals using an external force of about∼3.6 MPa.The modified layer has been characterized using a micro-Raman method to determine residual stress.The sliced surface exhibits a combination of smooth and coarse appearances around the fluvial morphology,with an average surface roughness of over S_(a) 0.89μm.An amorphous phase surrounds the SiC substrate,with two dimensions of lattice spacing,d=0.261 nm and d=0.265 nm,confirmed by high-resolution transmission electron microscopy(HRTEM).The creation of laser-induced periodic surface nanostructures in the laser-polished surface results in a flatter surface with an average roughness of less than S_(a) 0.22μm.Due to the extreme cooling rates and multiple thermal cy-cles,dissociation of Si-C bonding,and phase separation are identified on the laser-polished surface,which is much better than that of the machining surface.We anticipate that this approach will be applicable to other high-value crystals and will have promising viability in the aerospace and semiconductor industries.展开更多
The enhanced performance of aerospace equipment drives parts development towards integration,complexity,and structural optimization.This advancement promotes metal near-net fabrication technologies like wire electrica...The enhanced performance of aerospace equipment drives parts development towards integration,complexity,and structural optimization.This advancement promotes metal near-net fabrication technologies like wire electrical discharge machining(WEDM)and 3D printing.However,the high initial surface roughness from WEDM or 3D printing poses significant challenges for the high-performance surface finishing required.To effectively reduce the surface roughness of the workpieces with high initial surface roughness,this paper proposes pulsed unipolar-polarisation plasma electrolytic polishing(PUP-PEP).The study examined the material removal mechanisms and surface polishing quality of PUP-PEP.This technique combines the high current density and material removal rate of the electrolytic polishing mode with the superior surface polishing quality of PEP through voltage waveform modulation.For an Inconel-718 superalloy part fabricated by WEDM,PUP-PEP reduced surface roughness from R_(a)7.39μm to R_(a)0.27μm in 6 min under optimal conditions.The roughness decreased from R_(a)7.39μm to R_(a)0.78μm in the first 3 min under pulsed unipolar-polarisation voltage,resulting in a remarkable 233%increase in efficiency compared to that with conventional PEP.Subsequently,the voltage output voltage is transformed into a constant voltage mode,and PEP is continued based on PUP-PEP to finally reduce the workpiece surface roughness value to R_(a)0.27μm.The proposed PUP-PEP technology marks the implementation of‘polishing’instead of conventional rough-finish machining processes,presenting a new approach to the surface post-processing of metal near-net fabrication technologies.展开更多
Diamond is a highly valuable material with diverse industrial applications,particularly in the fields of semiconductor,optics,and high-power electronics.However,its high hardness and chemical stability make it difficu...Diamond is a highly valuable material with diverse industrial applications,particularly in the fields of semiconductor,optics,and high-power electronics.However,its high hardness and chemical stability make it difficult to realize high-efficiency and ultra-low damage machining of diamond.To address these challenges,several polishing methods have been developed for both single crystal diamond(SCD)and polycrystalline diamond(PCD),including mechanical,chemical,laser,and ion beam processing methods.In this review,the characteristics and application scope of various polishing technologies for SCD and PCD are highlighted.Specifically,various energy beam-based direct and assisted polishing technologies,such as laser polishing,ion beam polishing,plasma-assisted polishing,and laser-assisted polishing,are summarized.The current research progress,material removal mechanism,and infuencing factors of each polishing technology are analyzed.Although some of these methods can achieve high material removal rates or reduce surface roughness,no single method can meet all the requirements.Finally,the future development prospects and application directions of different polishing technologies are presented.展开更多
Ceramic cutting inserts are a type of cutting tool commonly used in high-speed metal cutting applications.However,the wear of these inserts caused by friction between the workpiece and cutting inserts limits their ove...Ceramic cutting inserts are a type of cutting tool commonly used in high-speed metal cutting applications.However,the wear of these inserts caused by friction between the workpiece and cutting inserts limits their overall effectiveness.In order to improve the tool life and reduce wear,this study introduces an emerging method called magnetic field-assisted batch polishing(MABP)for simultaneously polishing multiple ceramic cutting inserts.Several polishing experiments were conducted under different conditions,and the wear characteristics were clarified by cutting S136H steel.The results showed that after 15 min of polishing,the surface roughness at the flank face,edge,and nose of the inserts was reduced to below 2.5 nm,6.25 nm,and 45.8 nm,respectively.Furthermore,the nose radii of the inserts did not change significantly,and there were no significant changes in the weight percentage of elements before and after polishing.Additionally,the tool life of the batch polished inserts was found to be up to 1.75 times longer than that of unpolished inserts.These findings suggest that the MABP method is an effective way to mass polish ceramic cutting inserts,resulting in significantly reduced tool wear.Furthermore,this novel method offers new possibilities for polishing other tools.展开更多
Removal of milling marks at the root fillet of titanium alloy blade is a tough work because of the interference between the polishing tool and the workpiece.A polishing method based on elastic magnetic tool was propos...Removal of milling marks at the root fillet of titanium alloy blade is a tough work because of the interference between the polishing tool and the workpiece.A polishing method based on elastic magnetic tool was proposed.The software ANSYS Maxwell was used to simulate the effect of different pole orientation arrangements on the magnetic field distribution.A comparison of polishing effect was made between elastic and inelastic magnetic pole carriers.The processing parameters of the elastic magnetic tool polishing for the blade root were optimized by orthogonal experiment(Taguchi)method.Results show that compared with the inelastic magnetic polishing tool,the elastic magnetic polishing tool with polyurethane as the pole carrier can effectively improve the surface quality of the polished workpiece.Under the optimal processing parameters(rotational speed=900 r/min,feeding rate=6 mm/min,machining gap=1.5 mm and abrasive size=10‒14μm),the original milling marks at the blade root are effectively removed and the average surface roughness Ra is dropped from 0.95μm to 0.12μm,which verifies the feasibility of the elastic magnetic polishing tool in the surface finishing of the titanium alloy blade root.展开更多
Millets are widely recognized for their nutritional significance;however, the methods employed for their processing are currently lacking. This article primarily focuses on the advanced technologies and progressions i...Millets are widely recognized for their nutritional significance;however, the methods employed for their processing are currently lacking. This article primarily focuses on the advanced technologies and progressions in millet dehulling and polishing. These technologies operate based on the fundamental principles of compression-shearing, abrasion-friction, and centrifugal-impact forces. Processing of millets can be challenging because of the physical characteristics and tight attachment of hull and bran to the endosperm. However, several dehullers have been designed to solve this problem for different kinds of millets. In addition, the nutritional and anti-nutritional characteristics undergo alterations due to both dehulling and polishing processes. These alterations are thoroughly examined and discussed in this article. Specifically, anti-nutrients such as tannins and phytate are predominantly found in the outer pericarp of the grain and experience a reduction after undergoing dehulling and polishing. The nutritional properties are also subjected to a reduction;however, this reduction can be mitigated by subjecting the grains to certain pretreatments before dehulling and polishing. These treatments serve to enhance dehulling efficiency and nutrient digestibility while simultaneously reducing the presence of anti-nutrients. Novel thermal and non-thermal methodologies such as microwave, hydrothermal, high-pressure processing, and ohmic heating can be employed for processing millets, thereby diminishing the loss of nutrients. Additional research can be carried out to investigate their impact on the dehulling and polishing of millets.展开更多
PINGYAO hand-polished lacquerware has been widely considered as one of the four most famed lacquerware types in China.It originated more than 2,000 years ago in what is called Pingyao County today,in Jinzhong City,cen...PINGYAO hand-polished lacquerware has been widely considered as one of the four most famed lacquerware types in China.It originated more than 2,000 years ago in what is called Pingyao County today,in Jinzhong City,central China’s Shanxi Province.Its fame is due to the exquisite and unique skill of polishing lacquered coating with bare hands during the manufacturing process.This quaint and durable lacquerware boasts both aesthetic and practical values,and is characterized by its distinguished appearance and glossy sheen.It comes in the forms of jewelry boxes,utensils and stationery,screens and furniture.展开更多
We present an improved angle polishing method in which the end of the cover slice near the glue layer is beveled into a thin,defect-free wedge,the straight edge of which is used as the datum for measuring the depth of...We present an improved angle polishing method in which the end of the cover slice near the glue layer is beveled into a thin,defect-free wedge,the straight edge of which is used as the datum for measuring the depth of subsurface damage. The bevel angle can be calculated from the interference fringes formed in the wedge. The minimum depth of the subsurface damage that can be measured by this method is a few hundred nanometers. Our results show that the method is straightforward, accurate, and convenient.展开更多
The granule shape and crystal structure of the the ceria-based rare earth oxide which were roasted at 600～1050 ℃ for 2～6 h and then cooled in furnace, cooled out of furnace or cooled in water were studied by means ...The granule shape and crystal structure of the the ceria-based rare earth oxide which were roasted at 600～1050 ℃ for 2～6 h and then cooled in furnace, cooled out of furnace or cooled in water were studied by means of XRD and SEM. The results revealed that the rich cerium rare earth carbonate could be changed into the rare earth oxide which was a kind of sandwich made of globose granule whose diameter was between 0.5～3.0 μm after being roasted in 900 ℃ for 2 h. This kind of crystal lattice in rare earth oxide belonged to face-centered cubic lattice and its space between crystal surface {111} and {200} (viz. L111 and L200) would enlarge as the roasting temperature increasing. With increasing roasting temperature, L111 would rise straightly upward, and L200 would rise straightly upward when roasting time was 2～4 h but changed little when roasting time was 4～6 h. The glass-polishing experiments found that the polishing ability of the ceria-based rare earth oxide was the best as L111 was 43～53 nm and the L200 was 43～56 nm.展开更多
In order to improve the polishing ability of polishing pads, a kind of polishing pad with the tin fixed abrasive blocks, which are arranged based on the phyllotaxis theory of biology, was designed and fabricated by th...In order to improve the polishing ability of polishing pads, a kind of polishing pad with the tin fixed abrasive blocks, which are arranged based on the phyllotaxis theory of biology, was designed and fabricated by the use of electroplating technology, and also its polishing ability for JGS-2 wafer was investigated by polishing experiments. The research results show that the phyllotactic parameters of the polishing pad influence the arrangement density of the tin fixed abrasive blocks, the polishing pad with phyllotactic pattern is feasibly fabricated by the use of electroplating technology, and the good polishing result can be obtained by using the polishing pad with phyllotactic pattern to polish a wafer when the diameter D of the tin fixed abrasive block is between Φ1.3 mm and Φ1.4 mm, and the phyllotactic coefficient k between 1.0 and 1.1,respectively.展开更多
文摘The Fenton-like reaction between Cu^(2+)and H_(2)O_(2)was employed in chemical mechanical polishing to achieve efficient and high-quality processing of tungsten.The microstructure evolution and material removal rate of tungsten during polishing process were investigated via scanning electron microscopy,X-ray photoelectron spectroscopy,ultraviolet−visible spectrophotometry,and electrochemical experiments.The passivation behavior and material removal mechanism were discussed.Results show that the use of mixed H_(2)O_(2)+Cu(NO_(3))_(2)oxidant can achieve higher polishing efficiency and surface quality compared with the single oxidant Cu(NO_(3))_(2)or H_(2)O_(2).The increase in material removal rate is attributed to the rapid oxidation of W into WO_(3)via the chemical reaction between the substrate and hydroxyl radicals produced by the Fenton-like reaction.In addition,material removal rate and static etch rate exhibit significantly different dependencies on the concentration of Cu(NO_(3))_(2),while the superior oxidant for achieving the balance between polishing efficiency and surface quality is 0.5 wt.%H_(2)O_(2)+1.0 wt.%Cu(NO_(3))_(2).
基金Project supported by the National Natural Science Foundation of China (21971129, 21961022, 21661023)the Inner Mongolia Autonomous Region 2022 Leading Talent Team of Science and Technology (2022LJRC0008)+6 种基金the Natural Science Foundation of Inner Mongolia Autonomous Region of China(2022MS02014, 2021BS02007)the Program for Innovative Research Team in Universities of Inner Mongolia Autonomous Region (NJYT23031)the 111 Project(D20033)the “Grassland Leading Talent” Program of Inner Mongoliathe “Grassland-Talent” Innovation Team of Inner Mongoliathe “Science and Technology for a Better Development of Inner Mongolia” Program (2020XM03)the Science and Technology Project of Ordos (2021 ZDI 11-14)。
文摘CeO_(2)is increasingly recognized as a viable polishing abrasive for SiO_(2)-based substrates,such as K9 glass,leveraging its intrinsic chemical mechanical polishing property.Although LaOF can improve the performance of CeO_(2)abrasive,the specific mechanism underlying this enhancement remains elusive.Herein,LaOF-CeO_(2)composite abrasive was prepared by co-precipitation method,aiming to elaborate on the influence of LaOF on the abrasive's polishing efficiency.It is found that the integration of LaOF results in the formation of LaOF-CeO_(2)composite characterized by a remarkably reduced primary particle size of approximately 41 nm,which primarily accounts for the improvement in polishing performance.Furthermore,the increasement in Ce^(3+)content and the Zeta potential both contribute to the superior function of the composite abrasive.Notably,the synergistic effect of these parameters is manifested in an elevated material removal rate reaching 1091.197 nm/min,coupled with a minimized surface roughness of as low as 0.546 nm when applied to K9 glass surface.The findings of this work offer novel insights into the role of LaOF in facilitating the performance of Ce-based abrasives,potentially influencing future advancements in the field of precision surface processing.
基金Project supported by the National Key Research and Development Program(2021YFB3501101)Beijing Nova Program(20220484827)+2 种基金National Natural Science Foundation of China(52304370)Central Government Guidance Local Science and Technology Development Fund Project of Hebei Province(236Z4102G)Natural Science Foundation of Hebei Province(E2022103012)。
文摘Rare earth carbonates are essential precursors for the synthesis of oxide materials.In this study,we utilized in situ monitoring equipment to explore the alterations in the crystallization during the coprecipitation synthesis of cerium carbonate.By controlling the crystallization pathway and in the absence of any te mplating agents,we successfully synthesized a unique sphe rical self-assembled cerium oxide particle(Ceria-S).The Ceria-S exhibits excellent polishing performance.The crystallization process of cerium carbonate at 50℃persists for roughly 50 min.During the initial stages of crystallization from 0 to t_(3),the precipitated particles are amorphous.This is followed by a plateau phase of crystal growth from t_(3)to t_(5).Subsequently,during the burst crystallization phase from t_(5)to t_(6),Ce_(2)(CO_(3))_(3)·6H_(2)O and Ce_(2)O(CO_(3))_(2)·nH2O are formed,exhibiting a rod-like crystal morphology.By rapidly drying the precipitated particles at 60℃for 10 min and calcining,Ceria-S is obtained.The Ceria-S,with an average diameter of 180 nm,is assembled from primary cerium oxide nanoparticles of approximately 15 nm.Owing to the self-assembly structure of cerium oxide spherical nanoparticles,they exhibit a significantly larger specific surface area,resulting in an elevated concentration of Ce^(3+)as high as 35.5%.The Ceria-S exhibits a polishing removal rate of 420 nm/min,effectively decreasing the surface roughness(S_(a))of K9 glass from 1.605 to 0.404 nm.
基金supported by the National Key Research and Development Program(2021YFB3501103)Guiding Local Funding Projects for Scientific and Technological Development by Central Government in Hebei(216Z1402G)Youth Fund of GRINM Group Co.,Ltd.
文摘The lanthanum-cerium-based slurry(LC-slurry)is extensively utilized in the chemical mechanical polishing(CMP)of TFT-LCD glass substrates,optical lenses,and other glass products.Sodium hexametaphosphate(SHMP),as a dispersant,is commonly employed to enhance the dispersion properties of LCslurry for improved polishing performance.However,the tendency of sedimentation to form a compacted sediment layer,which is challenging to redisperse,increases storage difficulty and polishing equipment failure risk,thereby limiting its utilization in CMP.In the present study,sodium carboxymethylcellulose(CMC-Na),a long-chain organic polymer,was employed to enhance the redispersibility of LC-slurry containing SHMP.A comprehensive investigation was conducted on the influence of CMC-Na dosage and slurry pH on dispersibility,redispersibility and polishing performance.Additionally,an analysis was carried out to elucidate the underlying mechanism behind the effect of CMC-Na.The study demonstrates that the LC-slurry,containing 250 ppm SHMP and 500 ppm CMC-Na,exhibits excellent dispersibility and redispersibility.Further polishing tests demonstrate that compared to the LC-slurry containing only SHMP,utilizing the slurry containing both SHMP and CMC-Na at various pH for polishing thin film transistor liquid crystal display(TFT-LCD)glass substrates results in a reduction of both material removal rate(MRR)and surface roughness(Sa).Specifically,when adjusting the slurry to a pH range of 5-6,the MRR can reach up to 330 nm/min,which closely approximates the MRR achieved by LC-slurry containing only 250 ppm SHMP at corresponding pH values.Meanwhile,after polishing,the surface roughness of the glass substrate measures approximately 0.47 nm.
基金supported by the National Natural Science Foundation of China(Nos.51974196,52275361,and 52305406)the Key Projects of the National Natural Science Foundation of China(No.U22A20188)the Special Projects of the Central Government in Guidance of Local Science and Technology Development(YDZX20191400002149).
文摘The textured roll and polished roll were applied instead of the ground roll in a 20-high mill to conduct two-pass rolling of 316L stainless steel strip with thickness of 0.027 mm.After the two-pass rolling with the textured roll and polished roll(TPR),the surface roughness of the strip is dramatically reduced,and the surface topographical anisotropy index is diminished to 30.9%of the initial strip.Comparing with the strip rolled using the ground roll in both passes(GGR),the elongation of TPR rolled strip is obviously improved,and the mechanical property anisotropy is greatly weakened.The anisotropy index of tensile strength and elongation are 42.58%and 52.59%of that of GGR rolled strip,which is mainly attributed to the significant decrease of the texture intensity of the strip by TPR process.The results indicate that TPR process can obtain the stainless steel ultra-thin strip with smooth and uniform surface topography and good mechanical properties.
基金financial support from the National Key Research and Development Program of China(2018YFA0703400)the Fundamental Research Funds for the Provincial Universities of Zhejiang(GK239909299001021)+1 种基金the Ninth China Association for Science and Technology Youth Talent Lift Project Support Plan(KYZ015324002)the Changjiang Scholars Program of Chinese Ministry of Education。
文摘Atomic surfaces are strictly required by high-performance devices of diamond.Nevertheless,diamond is the hardest material in nature,leading to the low material removal rate(MRR)and high surface roughness during machining.Noxious slurries are widely used in conventional chemical mechanical polishing(CMP),resulting in the possible pollution to the environment.Moreover,the traditional slurries normally contain more than four ingredients,causing difficulties to control the process and quality of CMP.To solve these challenges,a novel green CMP for single crystal diamond was developed,consisting of only hydrogen peroxide,diamond abrasive and Prussian blue(PB)/titania catalyst.After CMP,atomic surface is achieved with surface roughness Sa of 0.079 nm,and the MRR is 1168 nm·h^(-1).Thickness of damaged layer is merely 0.66 nm confirmed by transmission electron microscopy(TEM).X-ray photoelectron spectroscopy,electron paramagnetic resonance and TEM reveal that·OH radicals form under ultraviolet irradiation on PB/titania catalyst.The·OH radicals oxidize diamond,transforming it from monocrystalline to amorphous atomic structure,generating a soft amorphous layer.This contributes the high MRR and formation of atomic surface on diamond.The developed novel green CMP offers new insights to achieve atomic surface of diamond for potential use in their high-performance devices.
文摘On March 19,CIIS President Chen Bo met with Wojciech Zajączkowski,Director of the Asia-Pacific Department of the Ministry of Foreign Affairs of Poland.CIIS Vice President Liu Feitao moderated a discussion with the delegation led by Director Zajączkowski.The two sides exchanged in-depth views on the current China-Europe relations,China-Poland relations,and the Ukraine crisis.
基金the National Key Research and Development Program of China(2018YFA0703400)the Young Scientists Fund of the National Natural Science Foundation of China(52205447)Changjiang Scholars Program of the Chinese Ministry of Education。
文摘It is a challenge to polish the interior surface of an additively manufactured component with complex structures and groove sizes less than 1 mm.Traditional polishing methods are disabled to polish the component,meanwhile keeping the structure intact.To overcome this challenge,small-grooved components made of aluminum alloy with sizes less than 1 mm were fabricated by a custom-made printer.A novel approach to multi-phase jet(MPJ)polishing is proposed,utilizing a self-developed polisher that incorporates solid,liquid,and gas phases.In contrast,abrasive air jet(AAJ)polishing is recommended,employing a customized polisher that combines solid and gas phases.After jet polishing,surface roughness(Sa)on the interior surface of grooves decreases from pristine 8.596μm to 0.701μm and 0.336μm via AAJ polishing and MPJ polishing,respectively,and Sa reduces 92%and 96%,correspondingly.Furthermore,a formula defining the relationship between linear energy density and unit defect volume has been developed.The optimized parameters in additive manufacturing are that linear energy density varies from 0.135 J mm^(-1)to 0.22 J mm^(-1).The unit area defect volume achieved via the optimized parameters decreases to 1/12 of that achieved via non-optimized ones.Computational fluid dynamics simulation results reveal that material is removed by shear stress,and the alumina abrasives experience multiple collisions with the defects on the heat pipe groove,resulting in uniform material removal.This is in good agreement with the experimental results.The novel proposed setups,approach,and findings provide new insights into manufacturing complex-structured components,polishing the small-grooved structure,and keeping it unbroken.
基金supported by National Key Research and Development Program of China(Grant No.2022YFB4600901).
文摘Additive manufacturing(AM)is a reliable technique for constructing highly complex metallic parts.Direct energy deposition(DED)is one of the most common technologies used for AM-printed metal alloys.However,issues such as weak binding,poor accuracy,and rough surfaces still affect the final products.These limitations in the metal-feed DED process indicate that post-processing techniques are required to achieve high quality in terms of both mechanical properties and surface finish.Conventional contact-based post-processing methods have several drawbacks,including difficulties in accessing complex shapes,environmental impact,high time consumption and cost,and health risks for operators.To address these problems and improve surface quality,a laser polishing process has been proposed.By melting or ablating the material with a laser,the laser-polishing process enables the smoothing of the initial topography.It should be noted that there are currently no reviews focusing specifically on laser polishing as a surface treatment technology for the DED process.Therefore,this review presents a unique examination of the mechanisms and primary user-set parameters for both continuous wave(CW)and pulsed laser polishing.The objective is to demonstrate the capabilities of each process and the benefits of using them for the surfaces of DED metal parts.Additionally,existing knowledge and technology gaps are identified,and future research directions are discussed.
基金supported by National Natural Science Foundation of China(No.62304249)a project funded by China Postdoctoral Science Foundation(No.2023M733704).
文摘Slicing and post-treatment of SiC crystals have been a significant challenge in the integrated circuit and microelectronics industry.To compete with wire-sawing and mechanical grinding technology,a promis-ing approach combining laser slicing and laser polishing technologies has been innovatively applied to increase utilization and decrease damage defects for single crystal 4H-SiC.Significant material utiliza-tion has been achieved in the hybrid laser processes,where material loss is reduced by 75%compared to that of conventional machining technologies.Without any special process control or additional treat-ment,an internally modified layer formed by laser slicing can easily separate the 4H-SiC crystals using an external force of about∼3.6 MPa.The modified layer has been characterized using a micro-Raman method to determine residual stress.The sliced surface exhibits a combination of smooth and coarse appearances around the fluvial morphology,with an average surface roughness of over S_(a) 0.89μm.An amorphous phase surrounds the SiC substrate,with two dimensions of lattice spacing,d=0.261 nm and d=0.265 nm,confirmed by high-resolution transmission electron microscopy(HRTEM).The creation of laser-induced periodic surface nanostructures in the laser-polished surface results in a flatter surface with an average roughness of less than S_(a) 0.22μm.Due to the extreme cooling rates and multiple thermal cy-cles,dissociation of Si-C bonding,and phase separation are identified on the laser-polished surface,which is much better than that of the machining surface.We anticipate that this approach will be applicable to other high-value crystals and will have promising viability in the aerospace and semiconductor industries.
基金Supported by National Natural Science Foundation of China(Grant No.52205476)the Youth Talent Support Project of Jiangsu Provincial Association of Science and Technology(Grant No.TJ-2023-070)+1 种基金the Fund of Prospective Layout of Scientific Research for Nanjing University of Aeronautics and Astronautics(Grant No.1005-ILB23025-1A)the Fund of Jiangsu Key Laboratory of Precision and Micro-Manufacturing Technology(Grant No.1005-ZAA20003-14).
文摘The enhanced performance of aerospace equipment drives parts development towards integration,complexity,and structural optimization.This advancement promotes metal near-net fabrication technologies like wire electrical discharge machining(WEDM)and 3D printing.However,the high initial surface roughness from WEDM or 3D printing poses significant challenges for the high-performance surface finishing required.To effectively reduce the surface roughness of the workpieces with high initial surface roughness,this paper proposes pulsed unipolar-polarisation plasma electrolytic polishing(PUP-PEP).The study examined the material removal mechanisms and surface polishing quality of PUP-PEP.This technique combines the high current density and material removal rate of the electrolytic polishing mode with the superior surface polishing quality of PEP through voltage waveform modulation.For an Inconel-718 superalloy part fabricated by WEDM,PUP-PEP reduced surface roughness from R_(a)7.39μm to R_(a)0.27μm in 6 min under optimal conditions.The roughness decreased from R_(a)7.39μm to R_(a)0.78μm in the first 3 min under pulsed unipolar-polarisation voltage,resulting in a remarkable 233%increase in efficiency compared to that with conventional PEP.Subsequently,the voltage output voltage is transformed into a constant voltage mode,and PEP is continued based on PUP-PEP to finally reduce the workpiece surface roughness value to R_(a)0.27μm.The proposed PUP-PEP technology marks the implementation of‘polishing’instead of conventional rough-finish machining processes,presenting a new approach to the surface post-processing of metal near-net fabrication technologies.
基金sponsored by the National Natural Science Foundation of China(Nos.51835004,U22A20198)the Major Science and Technology Projects in Henan Province(221100230300)the 111 Project(No.B23011)。
文摘Diamond is a highly valuable material with diverse industrial applications,particularly in the fields of semiconductor,optics,and high-power electronics.However,its high hardness and chemical stability make it difficult to realize high-efficiency and ultra-low damage machining of diamond.To address these challenges,several polishing methods have been developed for both single crystal diamond(SCD)and polycrystalline diamond(PCD),including mechanical,chemical,laser,and ion beam processing methods.In this review,the characteristics and application scope of various polishing technologies for SCD and PCD are highlighted.Specifically,various energy beam-based direct and assisted polishing technologies,such as laser polishing,ion beam polishing,plasma-assisted polishing,and laser-assisted polishing,are summarized.The current research progress,material removal mechanism,and infuencing factors of each polishing technology are analyzed.Although some of these methods can achieve high material removal rates or reduce surface roughness,no single method can meet all the requirements.Finally,the future development prospects and application directions of different polishing technologies are presented.
基金Supported by Research Grants Council of the Government of the Hong Kong Special Administrative Region of China (Grant No.15203620)Research and Innovation Office of The Hong Kong Polytechnic University of China (Grant Nos.BBXN,1-W308)+1 种基金Research Studentships (Grant No.RH3Y)State Key Laboratory of Mechanical System and Vibration of China (Grant No.MSV202315)。
文摘Ceramic cutting inserts are a type of cutting tool commonly used in high-speed metal cutting applications.However,the wear of these inserts caused by friction between the workpiece and cutting inserts limits their overall effectiveness.In order to improve the tool life and reduce wear,this study introduces an emerging method called magnetic field-assisted batch polishing(MABP)for simultaneously polishing multiple ceramic cutting inserts.Several polishing experiments were conducted under different conditions,and the wear characteristics were clarified by cutting S136H steel.The results showed that after 15 min of polishing,the surface roughness at the flank face,edge,and nose of the inserts was reduced to below 2.5 nm,6.25 nm,and 45.8 nm,respectively.Furthermore,the nose radii of the inserts did not change significantly,and there were no significant changes in the weight percentage of elements before and after polishing.Additionally,the tool life of the batch polished inserts was found to be up to 1.75 times longer than that of unpolished inserts.These findings suggest that the MABP method is an effective way to mass polish ceramic cutting inserts,resulting in significantly reduced tool wear.Furthermore,this novel method offers new possibilities for polishing other tools.
基金Joint Funds of the National Natural Science Foundation of China(U20A20293)。
文摘Removal of milling marks at the root fillet of titanium alloy blade is a tough work because of the interference between the polishing tool and the workpiece.A polishing method based on elastic magnetic tool was proposed.The software ANSYS Maxwell was used to simulate the effect of different pole orientation arrangements on the magnetic field distribution.A comparison of polishing effect was made between elastic and inelastic magnetic pole carriers.The processing parameters of the elastic magnetic tool polishing for the blade root were optimized by orthogonal experiment(Taguchi)method.Results show that compared with the inelastic magnetic polishing tool,the elastic magnetic polishing tool with polyurethane as the pole carrier can effectively improve the surface quality of the polished workpiece.Under the optimal processing parameters(rotational speed=900 r/min,feeding rate=6 mm/min,machining gap=1.5 mm and abrasive size=10‒14μm),the original milling marks at the blade root are effectively removed and the average surface roughness Ra is dropped from 0.95μm to 0.12μm,which verifies the feasibility of the elastic magnetic polishing tool in the surface finishing of the titanium alloy blade root.
基金the Indian Institute of Technology, Kharagpur, West Bengal, 721302, for providing technical and financial support for the research。
文摘Millets are widely recognized for their nutritional significance;however, the methods employed for their processing are currently lacking. This article primarily focuses on the advanced technologies and progressions in millet dehulling and polishing. These technologies operate based on the fundamental principles of compression-shearing, abrasion-friction, and centrifugal-impact forces. Processing of millets can be challenging because of the physical characteristics and tight attachment of hull and bran to the endosperm. However, several dehullers have been designed to solve this problem for different kinds of millets. In addition, the nutritional and anti-nutritional characteristics undergo alterations due to both dehulling and polishing processes. These alterations are thoroughly examined and discussed in this article. Specifically, anti-nutrients such as tannins and phytate are predominantly found in the outer pericarp of the grain and experience a reduction after undergoing dehulling and polishing. The nutritional properties are also subjected to a reduction;however, this reduction can be mitigated by subjecting the grains to certain pretreatments before dehulling and polishing. These treatments serve to enhance dehulling efficiency and nutrient digestibility while simultaneously reducing the presence of anti-nutrients. Novel thermal and non-thermal methodologies such as microwave, hydrothermal, high-pressure processing, and ohmic heating can be employed for processing millets, thereby diminishing the loss of nutrients. Additional research can be carried out to investigate their impact on the dehulling and polishing of millets.
文摘PINGYAO hand-polished lacquerware has been widely considered as one of the four most famed lacquerware types in China.It originated more than 2,000 years ago in what is called Pingyao County today,in Jinzhong City,central China’s Shanxi Province.Its fame is due to the exquisite and unique skill of polishing lacquered coating with bare hands during the manufacturing process.This quaint and durable lacquerware boasts both aesthetic and practical values,and is characterized by its distinguished appearance and glossy sheen.It comes in the forms of jewelry boxes,utensils and stationery,screens and furniture.
文摘We present an improved angle polishing method in which the end of the cover slice near the glue layer is beveled into a thin,defect-free wedge,the straight edge of which is used as the datum for measuring the depth of subsurface damage. The bevel angle can be calculated from the interference fringes formed in the wedge. The minimum depth of the subsurface damage that can be measured by this method is a few hundred nanometers. Our results show that the method is straightforward, accurate, and convenient.
文摘The granule shape and crystal structure of the the ceria-based rare earth oxide which were roasted at 600～1050 ℃ for 2～6 h and then cooled in furnace, cooled out of furnace or cooled in water were studied by means of XRD and SEM. The results revealed that the rich cerium rare earth carbonate could be changed into the rare earth oxide which was a kind of sandwich made of globose granule whose diameter was between 0.5～3.0 μm after being roasted in 900 ℃ for 2 h. This kind of crystal lattice in rare earth oxide belonged to face-centered cubic lattice and its space between crystal surface {111} and {200} (viz. L111 and L200) would enlarge as the roasting temperature increasing. With increasing roasting temperature, L111 would rise straightly upward, and L200 would rise straightly upward when roasting time was 2～4 h but changed little when roasting time was 4～6 h. The glass-polishing experiments found that the polishing ability of the ceria-based rare earth oxide was the best as L111 was 43～53 nm and the L200 was 43～56 nm.
基金Sponsored by the National Nature Science Foundation of China (50875179)
文摘In order to improve the polishing ability of polishing pads, a kind of polishing pad with the tin fixed abrasive blocks, which are arranged based on the phyllotaxis theory of biology, was designed and fabricated by the use of electroplating technology, and also its polishing ability for JGS-2 wafer was investigated by polishing experiments. The research results show that the phyllotactic parameters of the polishing pad influence the arrangement density of the tin fixed abrasive blocks, the polishing pad with phyllotactic pattern is feasibly fabricated by the use of electroplating technology, and the good polishing result can be obtained by using the polishing pad with phyllotactic pattern to polish a wafer when the diameter D of the tin fixed abrasive block is between Φ1.3 mm and Φ1.4 mm, and the phyllotactic coefficient k between 1.0 and 1.1,respectively.
