Nanoparticle reinforced nickel matrix composite coatings, such as n-Al2O3/Ni, n-SiO2/Ni, n-SiC/Ni and n-TiO2/Ni, were fabricated by brush plating technique. Hardness, wear resistance and contact-fatigue resistance of ...Nanoparticle reinforced nickel matrix composite coatings, such as n-Al2O3/Ni, n-SiO2/Ni, n-SiC/Ni and n-TiO2/Ni, were fabricated by brush plating technique. Hardness, wear resistance and contact-fatigue resistance of the composite coatings were determined, and strengthening mechanism of the composite coatings was discussed. Results show that the composite coatings have superior properties to the Ni metal coating. Compared with properties of brush plated Ni metal coating, the composite coatings have hardness over 1.5 times and wear resistance capability of about 2.5 times. The strengthening mechanism of the composite coatings mainly includes fine-crystal grain effect, nanoparticle dispersion effect and dislocation effect.展开更多
A new theory and method that differs from the tradition-al single plated weft - knitting theory and method hasbeen expounded after theoretical analyzing and experi-mental proving. If the new method is used when platin...A new theory and method that differs from the tradition-al single plated weft - knitting theory and method hasbeen expounded after theoretical analyzing and experi-mental proving. If the new method is used when platingstitch is knitted on large diameter weft knitting machine,the thorny problem of long standing that ground yarn iseasy to appear on the face side of fabric is solved. Thenew method, i.e, the production of physical ability oftraining uniform for serviceman has been used.展开更多
The electrochemical behavior of Cu-Zn-Al shape memory alloy (SMA) with andwithout electroless plated Ni-P was investigated by electrochemical methods, in artificial Tyrode'ssolution. The results showed that Cu-Zn-...The electrochemical behavior of Cu-Zn-Al shape memory alloy (SMA) with andwithout electroless plated Ni-P was investigated by electrochemical methods, in artificial Tyrode'ssolution. The results showed that Cu-Zn-Al SMA engendered dezincification corrosion in Tyrode'ssolution. The anodic active current densities as well as electrochemical dissolution sensitivity ofthe electroless plated Ni-P Cu-Zn-Al SMA increased with NaCl concentration rising, pH of solutiondecreasing and environmental temperature uprising. X-ray diffraction analysis indicated that aftersurface modification by electroless plated Ni-P, an amorphous plated film formed on the surface ofCu-Zn-Al SMA. This film can effectively isolate matrix metal from corrosion media and significantlyimprove the electrochemical property of Cu-Zn-Al SMA in artificial Tyrode's solution.展开更多
In this paper the significance analysis has been made of the factors influencing the yarn appearing of single plated weft-knit fabrics knitted on large diameter machine by a mathematical statistical method. By means o...In this paper the significance analysis has been made of the factors influencing the yarn appearing of single plated weft-knit fabrics knitted on large diameter machine by a mathematical statistical method. By means of orthogonal test and variance analysis, it is known that the feeding tension is the significant factor influencing the yarn appearance and the ground yarn tension should be larger than the face yarn tension. Through comparison, it is also known that the drawing off force should be regulated suitably, the carrier should be near the first closed needle, and the sinker should be out late slightly.展开更多
The adhesion between the ion plated TiN coating and the base metal is improved by adding Y.The machenism of the effect of Y has been discussed as well.
A new phase was found at the interface between Al film and Ni substrate when the time of ion-plating reaches 5 min.It was identified to be body centered tetragonal lattice with the constants a=b=0.588 nm,c=0.480 nm.Th...A new phase was found at the interface between Al film and Ni substrate when the time of ion-plating reaches 5 min.It was identified to be body centered tetragonal lattice with the constants a=b=0.588 nm,c=0.480 nm.The variation of microstructure and phases with the ion-plating time were observed.Based on these results,the ion-plating film formation mech- anism has been also discussed.展开更多
The effect of rare earth(RE) additives on the quality of brush plated coating was studied by adding RE into brush plating solution. The results show that RE make the surface smooth and shiny, reduce residual stress ...The effect of rare earth(RE) additives on the quality of brush plated coating was studied by adding RE into brush plating solution. The results show that RE make the surface smooth and shiny, reduce residual stress within the coating and reinforced bond, and increase the wearability and corrosion resistance.展开更多
This paper reports the results of experimental research the longitudinal stiffeners in an orthotropic plated bridge deck on concerning the connection between the deck plate and the web of a microscopic scale. An impor...This paper reports the results of experimental research the longitudinal stiffeners in an orthotropic plated bridge deck on concerning the connection between the deck plate and the web of a microscopic scale. An important number of test specimens of a weld are studied with the help of a video microscope, to detect the efficiency of the root of the weld. The second part of the paper is concerned with parametric analysis of the lack of weld penetration by using accurate finite element modelling. The results demonstrate that the weld quality often required can not always be assured, which surely has important consequence on the stresses in the weld and the fatigue resistance.展开更多
Ni-plated glass beads（GB） was obtained by electroless plating, based on PVC adhesive, Niplated GB/PVC composite was prepared. Temperature insulation, fi re retardation and microwave absorption properties were tested...Ni-plated glass beads（GB） was obtained by electroless plating, based on PVC adhesive, Niplated GB/PVC composite was prepared. Temperature insulation, fi re retardation and microwave absorption properties were tested, the results showed that the nickel coating was compact and continuous, Ni-plated GB/ PVC composite is a kind of excellent temperature insulated, fi re retardate and light-weight material, and especially for microwave absorption well; Refl ectivity was lower than-2 dB in the frequency range of 11-17 GHz.展开更多
Wood is a kind of porous natural material with very poor electro-conductivity, and it has almost no function of electromagnetic shielding. The method of electroless nickel plating was used to produce wooden material w...Wood is a kind of porous natural material with very poor electro-conductivity, and it has almost no function of electromagnetic shielding. The method of electroless nickel plating was used to produce wooden material with electrical and effective electromagnetic shielding properties. Ni-P alloy layer was obtained on wood surface. The surface feature of plated wood veneer was observed by SEM and the surface composition and microstructure of the layer under different conditions were investigated by EDS and XRD respectively. Meanwhile, the relevant surface resistivity and electromagnetic shielding effectiveness were measured. Correlations of the phosphorous content in the layer to the structure of Ni-P alloy, electro-conductivity and electromagnetic shielding of plated veneers were discussed. SEM photos showed that the surface of electroless nickel plated veneers were covered with Ni-P alloy layer entirely, which made wood veneers more like metal. At the same time, the results showed that with the decreasing of the phosphorous content in the layer, the microstructure of Ni-P alloy layer transformed to be microcrystalline and electro-conductivity and electromagnetic shielding effectiveness were improved. When the phosphorous content was less than 2.37wt pct in the layer, the microstructure of Ni-P alloy layer was microcrystalline structure and its sur- face resistivity and electromagnetic shielding effectiveness were nearly 0.5Ω/□ and 55-60dB respectively.展开更多
Applying negative bias voltages caused significant microstructure changes in arc ion plated CrN films. Nanocrystalline microstructures were obtained by adjusting the negative bias voltage. Structural characterizations...Applying negative bias voltages caused significant microstructure changes in arc ion plated CrN films. Nanocrystalline microstructures were obtained by adjusting the negative bias voltage. Structural characterizations of the films were carried out using X-ray diffractometry (XRD) and high-resolution transmission electron microscopy (HR-TEM). The results indicated that increasing ion bombardment by applying negative bias voltages resulted in the formation of defects in the CrN films, inducing microstructure evolution from micro-columnar to nanocrystalline. The microhardness and residual stresses of the films were also affected. Based on the experimental results, the evolution mechanisms of the film microstructure and properties were discussed by considering ion bombardment effects.展开更多
In order to develop a more economical pretreatment method for electroless nickel plating, a dielectric barrier discharge （DBD） plasma at atmospheric pressure was used to improve the hydrophilicity and adhesion of po...In order to develop a more economical pretreatment method for electroless nickel plating, a dielectric barrier discharge （DBD） plasma at atmospheric pressure was used to improve the hydrophilicity and adhesion of poly （ethylene terephthalate） （PET） nonwoven fabric. The properties of the PET nonwoven fabric including its liquid absorptive capacity （WA）, aging behavior, surface chemical composition, morphology of the surface, adhesion strength, surface electrical resistivity and electromagnetic interference （EMI）- shielding effectiveness （SE） were studied. The liquid absorptive capacity （WA） increased due to the incorporation of oxygen-containing and nitrogen-containing functional groups on the surface of PET nonwoven fabric after DBD airplasma treatment. The surface morphology of the nonwoven fibers became rougher after plasma treatment. Therefore, the surface was more prone to absorb tin sensitizer and palladium catalyst to form an active layer for the deposition of electroless nickel. SEM and X-ray diffraction （XRD） measurements indicated that a uniform coating of nickel was formed on the PET nonwoven fabric. The average EMI-SE of Ni-plating of PET nonwoven fabric maintained a relatively stable value （38.2 dB to 37.3 dB） in a frequency range of 50 MHz to 1500 MHz. It is concluded that DBD is feasible for pretreatment of nonwoven fabric for electroless nickel plating to prepare functional material with good EMI-SE properties.展开更多
Single Ni-P and Ni-Mo-P coatings as well as duplex Ni-P/Ni-Mo-P coatings with the same compositions were prepared by electroless plating.The residual stresses of the coatings on the surface and cross sections were mea...Single Ni-P and Ni-Mo-P coatings as well as duplex Ni-P/Ni-Mo-P coatings with the same compositions were prepared by electroless plating.The residual stresses of the coatings on the surface and cross sections were measured by nanoindentation and AFM analysis,and the corrosion behaviour of the coatings in10%HCl solution was evaluated by electrochemical methods,to establish the correlation between the residual stresses and corrosion behaviour of the coatings.The results showed that the single Ni-P and duplex Ni-P/Ni-Mo-P coatings presented residual compressive stresses of241and206MPa respectively,while the single Ni-Mo-P coating exhibited a residual tensile stress of257MPa.The residual compressive stress impeded the growth of the pre-existing porosity in the coatings,protecting the integrity of the coating.The duplex Ni-P/Ni-Mo-P coatings had better corrosion resistance than their respective single coating.In addition,the stress states affect the corrosive form of coatings.展开更多
Ga_2O_3 metal–oxide–semiconductor field-effect transistors(MOSFETs) with high-breakdown characteristics were fabricated on a homoepitaxial n-typed β-Ga_2O_3 film, which was grown by metal organic chemical vapor dep...Ga_2O_3 metal–oxide–semiconductor field-effect transistors(MOSFETs) with high-breakdown characteristics were fabricated on a homoepitaxial n-typed β-Ga_2O_3 film, which was grown by metal organic chemical vapor deposition(MOCVD) on an Fedoped semi-insulating(010) Ga_2O_3 substrate. The structure consisted of a 400 nm unintentionally doped(UID) Ga_2O_3 buffer layer and an 80 nm Si-doped channel layer. A high k HfO_2 gate dielectric film formed by atomic layer deposition was employed to reduce the gate leakage. Moreover, a source-connected field plate was introduced to enhance the breakdown characteristics. The drain saturation current density of the fabricated device reached 101 mA/mm at V_(gs) of 3 V. The off-state current was as low as 7.1 ×10^(-11) A/mm, and the drain current I_(ON)/I_(OFF) ratio reached 10~9. The transistors exhibited three-terminal off-state breakdown voltages of 450 and 550 V, corresponding to gate-to-drain spacing of 4 and 8 μm, respectively.展开更多
TiAlSiN coating was deposited on H13 hot work mould steel using cathodic arc ion plating（CAIP）. The surface-interface morphologies and phases of the obtained coating were analyzed using field emission scanning elect...TiAlSiN coating was deposited on H13 hot work mould steel using cathodic arc ion plating（CAIP）. The surface-interface morphologies and phases of the obtained coating were analyzed using field emission scanning electron microscopy（FESEM） and X-ray diffraction（XRD）, respectively, and the morphologies, distributions of chemical elements and profiles of worn tracks were also researched using scanning electron microscopy（SEM）, energy disperse spectroscopy（EDS）, and optical microscope（OM）, respectively. The friction-wear performances of TiAlSiN coating under oil lubricated and dry fiction conditions were investigated, and the wear mechanisms of TiAlSiN coating were discussed. The experimental results show that the coating is primarily composed of（Ti, Al）N, AlTiN, and TiN hard phases, Si_3N_4 exists between the（Ti, Al）N crystal grains, increasing the coating microhardness to 3200 HV. The TiAlSiN coating has excellent performances of reducing friction and wear resistance, the average coefficient of friction（COF） of TiAlSiN coating under oil lubricated condition is only 0.05, lowered than the average COF of 0.211 under dry friction condition, the wear rate decreases by about 81.2% compared with that under dry friction condition. The wear mechanism of TiAlSiN coating under oil lubricated and dry friction conditions is composed of abrasive wear, fatigue wear, and abrasive wear, respectively. The internal friction of oil lubrication is a main factor of decreasing fatigue wear.展开更多
In this paper, the cross sectional microstructure and crystal structure of ion plated multi layer films of stainless steel (1Cr18Ni9Ti ) were studied by cross sectional transmission electron microscopy (XTEM). The re...In this paper, the cross sectional microstructure and crystal structure of ion plated multi layer films of stainless steel (1Cr18Ni9Ti ) were studied by cross sectional transmission electron microscopy (XTEM). The results show that ion plated stainless steel multi layer films are fine grained double phase steel films of austenites and ferrites.Cross section film growing microstructures can be divided into three zones: fine equiaxed crystals, fine columnar crystals and coarse columnar crystals. Interfaces in multi layer films can promote fine grained growing and interrupt columnar grained growing,and improve properties of film materials.展开更多
The autocatalytic deposition of Ni-Zn(Fe)-P alloys has been carried out on substrate of carbon steel from a bath containing nickel sulfate, zinc sulfate, sodium hypophosphite, sodium citrate and boric acid. The effect...The autocatalytic deposition of Ni-Zn(Fe)-P alloys has been carried out on substrate of carbon steel from a bath containing nickel sulfate, zinc sulfate, sodium hypophosphite, sodium citrate and boric acid. The effects of pH and the molar ratio of NiSO_4/ZnSO_4 on the deposition rate and the composition of deposits have been studied. It was found that the presence of zinc sulfate in the bath has an inhibitory effect on the alloy deposition. The structure and the surface morphology of Ni-Zn(Fe)-P coatings were characterized with XRD and SEM, respectively. The alloys plated under the experimental conditions consisted of an amorphous phase coexisting with a crystalline cubic Ni phase(poly-crystalline). The surface morphology of the coating is dependent on the deposition parameters. The corrosion resistance of the Ni-Zn(Fe)-P deposits was examined via mass loss tests and anodic polarization measurements, respectively. The results show that the surface morphologies of the deposits and the corrosion resistance of the deposits have been improved. The results of mass loss tests almost accord with those of anodic polarization measurements. The corrosion mechanisms of Ni-Zn(Fe)-P alloys in ~NaCl and NaOH solutions were investigated by means of EDX. The deposit immersed in an NaCl or an NaOH solution contains more content of oxygen and less contents of the metals(except Fe) than that placed in air, which shows that the NaCl or NaOH solution can accelerate the oxidation of the deposit.展开更多
Platinum-based bimetallic catalysts have broad applications in polymer electrolyte membrane fuel cells and water splitting. In this work,galvanic displacement reaction was employed to prepare Pt^Ni-P/CNT catalysts usi...Platinum-based bimetallic catalysts have broad applications in polymer electrolyte membrane fuel cells and water splitting. In this work,galvanic displacement reaction was employed to prepare Pt^Ni-P/CNT catalysts using electrolessly-plated Ni-P/CNT. These catalysts were extensively characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. Catalytic activities towards methanol oxidation and hydrogen evolution reactions were evaluated and benchmarked with a commercial Pt/C catalyst. Uniform dispersion of Pt on Ni-P particles led to high Pt utilization, and the electrochemical surface area of Pt^Ni-P/CNT with 12.1% Pt loading was found to be 126 m2 gà1, higher than that of a commercial Pt/C(77.9 m2 gà1). The Tafel slopes for the Pt^Ni-P/CNT catalysts were also found to be smaller than that of Pt/C indicating faster kinetics for hydrogen evolution reaction.展开更多
By a great deal of experiments,the misplating problemsof plated knitted fabrics composed of wool and Lycra arediscussed and analyzed.The factors affecting the mis-plating problems on manually operated flat knitting ma...By a great deal of experiments,the misplating problemsof plated knitted fabrics composed of wool and Lycra arediscussed and analyzed.The factors affecting the mis-plating problems on manually operated flat knitting ma-chine include the construction and adjustment of a plat-ing feeder,wool yarn count,feeding tension,takedowntension and the ground fabric structures.Some usefulresults can be derived from these works.展开更多
Investigation by using LAS 3000 surface analysis system showed that the oxide of Fe, Cr,Al formed during oxidation were Cr_2O_3,Fe_2O_3 and Al_2O_3,but only small amount of nickel oxide was found. The composition of o...Investigation by using LAS 3000 surface analysis system showed that the oxide of Fe, Cr,Al formed during oxidation were Cr_2O_3,Fe_2O_3 and Al_2O_3,but only small amount of nickel oxide was found. The composition of oxide layers for different oxidation durations varied in a similar way. In all cases,there exists an oxygen concentration peak in the composition profile of oxide layer. There is a transitional zone between oxide layer and alloy film.The thickness of oxide layer increases logarithmically with the time of oxida- tion.The ion plated Ni-Cr alloy film has very dense oxide layer and good oxidation resistance.展开更多
基金Project(G199906509) supported by the National Basic Research Program of China Project(2002M3) supported by China/UK Collaboration Subject Project(50235030) supported by the National Natural Science Foundation of China
文摘Nanoparticle reinforced nickel matrix composite coatings, such as n-Al2O3/Ni, n-SiO2/Ni, n-SiC/Ni and n-TiO2/Ni, were fabricated by brush plating technique. Hardness, wear resistance and contact-fatigue resistance of the composite coatings were determined, and strengthening mechanism of the composite coatings was discussed. Results show that the composite coatings have superior properties to the Ni metal coating. Compared with properties of brush plated Ni metal coating, the composite coatings have hardness over 1.5 times and wear resistance capability of about 2.5 times. The strengthening mechanism of the composite coatings mainly includes fine-crystal grain effect, nanoparticle dispersion effect and dislocation effect.
文摘A new theory and method that differs from the tradition-al single plated weft - knitting theory and method hasbeen expounded after theoretical analyzing and experi-mental proving. If the new method is used when platingstitch is knitted on large diameter weft knitting machine,the thorny problem of long standing that ground yarn iseasy to appear on the face side of fabric is solved. Thenew method, i.e, the production of physical ability oftraining uniform for serviceman has been used.
文摘The electrochemical behavior of Cu-Zn-Al shape memory alloy (SMA) with andwithout electroless plated Ni-P was investigated by electrochemical methods, in artificial Tyrode'ssolution. The results showed that Cu-Zn-Al SMA engendered dezincification corrosion in Tyrode'ssolution. The anodic active current densities as well as electrochemical dissolution sensitivity ofthe electroless plated Ni-P Cu-Zn-Al SMA increased with NaCl concentration rising, pH of solutiondecreasing and environmental temperature uprising. X-ray diffraction analysis indicated that aftersurface modification by electroless plated Ni-P, an amorphous plated film formed on the surface ofCu-Zn-Al SMA. This film can effectively isolate matrix metal from corrosion media and significantlyimprove the electrochemical property of Cu-Zn-Al SMA in artificial Tyrode's solution.
文摘In this paper the significance analysis has been made of the factors influencing the yarn appearing of single plated weft-knit fabrics knitted on large diameter machine by a mathematical statistical method. By means of orthogonal test and variance analysis, it is known that the feeding tension is the significant factor influencing the yarn appearance and the ground yarn tension should be larger than the face yarn tension. Through comparison, it is also known that the drawing off force should be regulated suitably, the carrier should be near the first closed needle, and the sinker should be out late slightly.
文摘The adhesion between the ion plated TiN coating and the base metal is improved by adding Y.The machenism of the effect of Y has been discussed as well.
文摘A new phase was found at the interface between Al film and Ni substrate when the time of ion-plating reaches 5 min.It was identified to be body centered tetragonal lattice with the constants a=b=0.588 nm,c=0.480 nm.The variation of microstructure and phases with the ion-plating time were observed.Based on these results,the ion-plating film formation mech- anism has been also discussed.
文摘The effect of rare earth(RE) additives on the quality of brush plated coating was studied by adding RE into brush plating solution. The results show that RE make the surface smooth and shiny, reduce residual stress within the coating and reinforced bond, and increase the wearability and corrosion resistance.
文摘This paper reports the results of experimental research the longitudinal stiffeners in an orthotropic plated bridge deck on concerning the connection between the deck plate and the web of a microscopic scale. An important number of test specimens of a weld are studied with the help of a video microscope, to detect the efficiency of the root of the weld. The second part of the paper is concerned with parametric analysis of the lack of weld penetration by using accurate finite element modelling. The results demonstrate that the weld quality often required can not always be assured, which surely has important consequence on the stresses in the weld and the fatigue resistance.
基金Funded in Part by the National Key Technology Research and Development Program of the Ministry of Science and Technology of China(No.2011BAC10B05)
文摘Ni-plated glass beads（GB） was obtained by electroless plating, based on PVC adhesive, Niplated GB/PVC composite was prepared. Temperature insulation, fi re retardation and microwave absorption properties were tested, the results showed that the nickel coating was compact and continuous, Ni-plated GB/ PVC composite is a kind of excellent temperature insulated, fi re retardate and light-weight material, and especially for microwave absorption well; Refl ectivity was lower than-2 dB in the frequency range of 11-17 GHz.
基金The research was supported by the National Hi-Tech R ＆ D Program （863） of China （2002AA24515）. Natural Science Foundation of Heilonjiang Province （C0210） and Harbin City Youth Science Fund （2004AFQXJ027）.
文摘Wood is a kind of porous natural material with very poor electro-conductivity, and it has almost no function of electromagnetic shielding. The method of electroless nickel plating was used to produce wooden material with electrical and effective electromagnetic shielding properties. Ni-P alloy layer was obtained on wood surface. The surface feature of plated wood veneer was observed by SEM and the surface composition and microstructure of the layer under different conditions were investigated by EDS and XRD respectively. Meanwhile, the relevant surface resistivity and electromagnetic shielding effectiveness were measured. Correlations of the phosphorous content in the layer to the structure of Ni-P alloy, electro-conductivity and electromagnetic shielding of plated veneers were discussed. SEM photos showed that the surface of electroless nickel plated veneers were covered with Ni-P alloy layer entirely, which made wood veneers more like metal. At the same time, the results showed that with the decreasing of the phosphorous content in the layer, the microstructure of Ni-P alloy layer transformed to be microcrystalline and electro-conductivity and electromagnetic shielding effectiveness were improved. When the phosphorous content was less than 2.37wt pct in the layer, the microstructure of Ni-P alloy layer was microcrystalline structure and its sur- face resistivity and electromagnetic shielding effectiveness were nearly 0.5Ω/□ and 55-60dB respectively.
基金Project(2010-0001-226) supported by the National Core Research Center (NCRC) Program through the National Research Foundation of Korea funded by the Ministry of Education, Science and TechnologyProject supported by the Fundamental R&D Program for Core Technology of Materials funded by the Ministry of Knowledge Economy, Korea
文摘Applying negative bias voltages caused significant microstructure changes in arc ion plated CrN films. Nanocrystalline microstructures were obtained by adjusting the negative bias voltage. Structural characterizations of the films were carried out using X-ray diffractometry (XRD) and high-resolution transmission electron microscopy (HR-TEM). The results indicated that increasing ion bombardment by applying negative bias voltages resulted in the formation of defects in the CrN films, inducing microstructure evolution from micro-columnar to nanocrystalline. The microhardness and residual stresses of the films were also affected. Based on the experimental results, the evolution mechanisms of the film microstructure and properties were discussed by considering ion bombardment effects.
基金supported by National Natural Science Foundation of China (No.50833003)
文摘In order to develop a more economical pretreatment method for electroless nickel plating, a dielectric barrier discharge （DBD） plasma at atmospheric pressure was used to improve the hydrophilicity and adhesion of poly （ethylene terephthalate） （PET） nonwoven fabric. The properties of the PET nonwoven fabric including its liquid absorptive capacity （WA）, aging behavior, surface chemical composition, morphology of the surface, adhesion strength, surface electrical resistivity and electromagnetic interference （EMI）- shielding effectiveness （SE） were studied. The liquid absorptive capacity （WA） increased due to the incorporation of oxygen-containing and nitrogen-containing functional groups on the surface of PET nonwoven fabric after DBD airplasma treatment. The surface morphology of the nonwoven fibers became rougher after plasma treatment. Therefore, the surface was more prone to absorb tin sensitizer and palladium catalyst to form an active layer for the deposition of electroless nickel. SEM and X-ray diffraction （XRD） measurements indicated that a uniform coating of nickel was formed on the PET nonwoven fabric. The average EMI-SE of Ni-plating of PET nonwoven fabric maintained a relatively stable value （38.2 dB to 37.3 dB） in a frequency range of 50 MHz to 1500 MHz. It is concluded that DBD is feasible for pretreatment of nonwoven fabric for electroless nickel plating to prepare functional material with good EMI-SE properties.
基金Project(ZR2011EMM014)supported by Shandong Provincial Natural Science Foundation of China
文摘Single Ni-P and Ni-Mo-P coatings as well as duplex Ni-P/Ni-Mo-P coatings with the same compositions were prepared by electroless plating.The residual stresses of the coatings on the surface and cross sections were measured by nanoindentation and AFM analysis,and the corrosion behaviour of the coatings in10%HCl solution was evaluated by electrochemical methods,to establish the correlation between the residual stresses and corrosion behaviour of the coatings.The results showed that the single Ni-P and duplex Ni-P/Ni-Mo-P coatings presented residual compressive stresses of241and206MPa respectively,while the single Ni-Mo-P coating exhibited a residual tensile stress of257MPa.The residual compressive stress impeded the growth of the pre-existing porosity in the coatings,protecting the integrity of the coating.The duplex Ni-P/Ni-Mo-P coatings had better corrosion resistance than their respective single coating.In addition,the stress states affect the corrosive form of coatings.
基金supported by the National Natural Science Foundation of China(Nos.61674130,61604137)
文摘Ga_2O_3 metal–oxide–semiconductor field-effect transistors(MOSFETs) with high-breakdown characteristics were fabricated on a homoepitaxial n-typed β-Ga_2O_3 film, which was grown by metal organic chemical vapor deposition(MOCVD) on an Fedoped semi-insulating(010) Ga_2O_3 substrate. The structure consisted of a 400 nm unintentionally doped(UID) Ga_2O_3 buffer layer and an 80 nm Si-doped channel layer. A high k HfO_2 gate dielectric film formed by atomic layer deposition was employed to reduce the gate leakage. Moreover, a source-connected field plate was introduced to enhance the breakdown characteristics. The drain saturation current density of the fabricated device reached 101 mA/mm at V_(gs) of 3 V. The off-state current was as low as 7.1 ×10^(-11) A/mm, and the drain current I_(ON)/I_(OFF) ratio reached 10~9. The transistors exhibited three-terminal off-state breakdown voltages of 450 and 550 V, corresponding to gate-to-drain spacing of 4 and 8 μm, respectively.
基金Funded by the Jiangsu Province Science and Technology Support Program(Industry)(BE2014865)
文摘TiAlSiN coating was deposited on H13 hot work mould steel using cathodic arc ion plating（CAIP）. The surface-interface morphologies and phases of the obtained coating were analyzed using field emission scanning electron microscopy（FESEM） and X-ray diffraction（XRD）, respectively, and the morphologies, distributions of chemical elements and profiles of worn tracks were also researched using scanning electron microscopy（SEM）, energy disperse spectroscopy（EDS）, and optical microscope（OM）, respectively. The friction-wear performances of TiAlSiN coating under oil lubricated and dry fiction conditions were investigated, and the wear mechanisms of TiAlSiN coating were discussed. The experimental results show that the coating is primarily composed of（Ti, Al）N, AlTiN, and TiN hard phases, Si_3N_4 exists between the（Ti, Al）N crystal grains, increasing the coating microhardness to 3200 HV. The TiAlSiN coating has excellent performances of reducing friction and wear resistance, the average coefficient of friction（COF） of TiAlSiN coating under oil lubricated condition is only 0.05, lowered than the average COF of 0.211 under dry friction condition, the wear rate decreases by about 81.2% compared with that under dry friction condition. The wear mechanism of TiAlSiN coating under oil lubricated and dry friction conditions is composed of abrasive wear, fatigue wear, and abrasive wear, respectively. The internal friction of oil lubrication is a main factor of decreasing fatigue wear.
文摘In this paper, the cross sectional microstructure and crystal structure of ion plated multi layer films of stainless steel (1Cr18Ni9Ti ) were studied by cross sectional transmission electron microscopy (XTEM). The results show that ion plated stainless steel multi layer films are fine grained double phase steel films of austenites and ferrites.Cross section film growing microstructures can be divided into three zones: fine equiaxed crystals, fine columnar crystals and coarse columnar crystals. Interfaces in multi layer films can promote fine grained growing and interrupt columnar grained growing,and improve properties of film materials.
文摘The autocatalytic deposition of Ni-Zn(Fe)-P alloys has been carried out on substrate of carbon steel from a bath containing nickel sulfate, zinc sulfate, sodium hypophosphite, sodium citrate and boric acid. The effects of pH and the molar ratio of NiSO_4/ZnSO_4 on the deposition rate and the composition of deposits have been studied. It was found that the presence of zinc sulfate in the bath has an inhibitory effect on the alloy deposition. The structure and the surface morphology of Ni-Zn(Fe)-P coatings were characterized with XRD and SEM, respectively. The alloys plated under the experimental conditions consisted of an amorphous phase coexisting with a crystalline cubic Ni phase(poly-crystalline). The surface morphology of the coating is dependent on the deposition parameters. The corrosion resistance of the Ni-Zn(Fe)-P deposits was examined via mass loss tests and anodic polarization measurements, respectively. The results show that the surface morphologies of the deposits and the corrosion resistance of the deposits have been improved. The results of mass loss tests almost accord with those of anodic polarization measurements. The corrosion mechanisms of Ni-Zn(Fe)-P alloys in ~NaCl and NaOH solutions were investigated by means of EDX. The deposit immersed in an NaCl or an NaOH solution contains more content of oxygen and less contents of the metals(except Fe) than that placed in air, which shows that the NaCl or NaOH solution can accelerate the oxidation of the deposit.
文摘Platinum-based bimetallic catalysts have broad applications in polymer electrolyte membrane fuel cells and water splitting. In this work,galvanic displacement reaction was employed to prepare Pt^Ni-P/CNT catalysts using electrolessly-plated Ni-P/CNT. These catalysts were extensively characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. Catalytic activities towards methanol oxidation and hydrogen evolution reactions were evaluated and benchmarked with a commercial Pt/C catalyst. Uniform dispersion of Pt on Ni-P particles led to high Pt utilization, and the electrochemical surface area of Pt^Ni-P/CNT with 12.1% Pt loading was found to be 126 m2 gà1, higher than that of a commercial Pt/C(77.9 m2 gà1). The Tafel slopes for the Pt^Ni-P/CNT catalysts were also found to be smaller than that of Pt/C indicating faster kinetics for hydrogen evolution reaction.
文摘By a great deal of experiments,the misplating problemsof plated knitted fabrics composed of wool and Lycra arediscussed and analyzed.The factors affecting the mis-plating problems on manually operated flat knitting ma-chine include the construction and adjustment of a plat-ing feeder,wool yarn count,feeding tension,takedowntension and the ground fabric structures.Some usefulresults can be derived from these works.
文摘Investigation by using LAS 3000 surface analysis system showed that the oxide of Fe, Cr,Al formed during oxidation were Cr_2O_3,Fe_2O_3 and Al_2O_3,but only small amount of nickel oxide was found. The composition of oxide layers for different oxidation durations varied in a similar way. In all cases,there exists an oxygen concentration peak in the composition profile of oxide layer. There is a transitional zone between oxide layer and alloy film.The thickness of oxide layer increases logarithmically with the time of oxida- tion.The ion plated Ni-Cr alloy film has very dense oxide layer and good oxidation resistance.
