Biodegradable implants from magnesium(Mg)alloys have emerged in the biomedical field especially in the orthopedic and cardiovascular stent applications owing to their low density,high specific strength,excellent machi...Biodegradable implants from magnesium(Mg)alloys have emerged in the biomedical field especially in the orthopedic and cardiovascular stent applications owing to their low density,high specific strength,excellent machinability,good biocompatibility,and biodegradability.The primary shortcoming of Mg-based implants is their low corrosion resistance in the physiological environment,which results in premature mechanical integrity loss before adequate healing and the production of excessive hydrogen gas,which is harmful to the body tissues and negatively affects the biocompatibility of the implant.Laser surface modification has recently received attention because it can improve the surface properties such as surface chemistry,roughness,topography,corrosion resistance,wear resistance,hydrophilicity,and thus cell response to the surface of the material.The composition and microstructures including textures and phases of laser-treated surfaces depend largely on the laser processing parameters(input laser power,laser scan velocity,frequency,pulse duration,pressure,gas circulation,working time,spot size,beam focal position,and laser track overlap)and the thermophysical properties of the substrate(solubility,melting point,and boiling point).This review investigates the impacts of various laser surface modification techniques including laser surface melting,laser surface alloying,laser cladding,laser surface texturing,and laser shock peening,and highlights their significance in improving the surface properties of biodegradable Mg alloys for implant applications.Additionally,we explore how different laser process parameters affect its composition,microstructure,and surface properties in each laser surface modification technique.展开更多
A bonding approach based on laser surface modification was developed to address the poor bonding be-tween Si_(3)N_(4) ceramic and Cu.The bonding mechanism in Si_(3)N_(4)/Cu heterogeneous composite structure fabricated...A bonding approach based on laser surface modification was developed to address the poor bonding be-tween Si_(3)N_(4) ceramic and Cu.The bonding mechanism in Si_(3)N_(4)/Cu heterogeneous composite structure fabricated by laser modification-assisted bonding is examined by means of scanning/transmission elec-tron microscopy and thermodynamic analysis.In the bonding process under laser modification,atomic intermixing at the interface is confirmed,as a result of the enhanced diffusion assisted by the dissocia-tion of Si_(3)N_(4) ceramic by laser.The dissociating Si precipitations on the surface,as well as the formation of micro-pores interfacial structure,would be the key concept of the bonding,by which the seamless and robust heterointerfaces were created.By controlling the laser-modifying conditions,we can obtain a reli-able heterostructure via the optimization of the trade-off of the surface structure and bonding strength,as determined by the laser-modified surface prior to bonding.The maximum structure depth and S ratio at the Si_(3)N_(4) surface were produced at a laser power of 56 W,corresponding to the maximal shear strength of 15.26 MPa.It is believed that the further development of this bonding technology will advance power electronic substrate fabrication applied in high-power devices.展开更多
A PVA-GAG-COL composite scaffold is fabricated by polyvinyl alcohol （PVA）, glyeosaminoglycan （GAG） and collagen （COL）. Laser surface modification technology is used to make holes on the surface of the scaffolds....A PVA-GAG-COL composite scaffold is fabricated by polyvinyl alcohol （PVA）, glyeosaminoglycan （GAG） and collagen （COL）. Laser surface modification technology is used to make holes on the surface of the scaffolds. Inside and outside interconnection micro-porous structure is obtained. Bioeompatibility test of the scaffolds shows that PVA-GAG-COL scaffold can promote the adhesion and proliferation of the fibroblast. Also, fibroblast can grow normally on the scaffolds with pore diameter from 115 um to 255 um and pore distance from 500 um to 2000 um. PVA-GAG-COL scaffolds possess excellent cell biocompatibility. The porous structure is suitable for cell culture in tissue engineering.展开更多
The surface of magnesium alloy was laser-processed,and the laser-etched morphology was determined as grooves by observing the surface morphology of sheep rib bone.The wettability of different morphologies was investig...The surface of magnesium alloy was laser-processed,and the laser-etched morphology was determined as grooves by observing the surface morphology of sheep rib bone.The wettability of different morphologies was investigated by contact angle test.Through the cell adhesion test,the effects of different morphologies on cell adhesion,growth and migration were investigated.Results show that the wetting angle of the block-shaped surface is smaller than that of the groove-shaped surface,and block-shaped surface has better hydrophilicity.Compared with the smooth surface,the block-shaped surface has better cell adhesion,and the depressions and bumps are full of cells,suggesting that the micropatterns prepared by the laser processing are conducive to the enhancement of biocompatibility.展开更多
Irradiated by infrared laser, the surface reducibility and adsorbability of Cu-Cr complex could be improved, owing to the interaction of photo-fragmentation and laser texturing. Analyzed by the binding energy spectra ...Irradiated by infrared laser, the surface reducibility and adsorbability of Cu-Cr complex could be improved, owing to the interaction of photo-fragmentation and laser texturing. Analyzed by the binding energy spectra and the auger spectra, the valence states of chromium ion and copper ion were+3 and+1 after radiation respectively, which still had the reducibility to release electrons. In contrast with the near-infrared(NIR)1 064 nm and mid-infrared(MIR) 10 600 nm laser at the same average output power of 15 W, the reduced metal percentage in the Cu-Cr complex was obviously distinguished at the depth from nanometer to micron. After chemical plating, the average coating thickness and mean-square deviation of the NIR sample were 11.61 μm and 0.30 for copper layer, and 2.69 μm and 0.08 for nickel layer. The results were much better than those of the MIR sample.展开更多
The surface modification of materials such as Ti-6Al-4V is necessary to improve their wear resistant properties for use in tribological applications. In this paper it is shown that a laser with low power and tungsten ...The surface modification of materials such as Ti-6Al-4V is necessary to improve their wear resistant properties for use in tribological applications. In this paper it is shown that a laser with low power and tungsten inert gas (TIG) can be combined together for surface modification of Ti-6Al-4V alloy, and when performed in a controlled atmosphere of pure nitrogen or a mixture of nitrogen and argon, can produce a wear-resistant surface alloy. Compared with laser processing, a cheaper surface modification process has been developed involving a shorter processing time, which is free of stringent requirements such as a vacuum system.展开更多
Thin metallic layers (~ 2 μm) of Ni were deposited on polycrystalline Al2O3. ZrO2 and (Ce-TZP)+Al2O3 ceramic substrates. and further irradiated with pulsed excimer (Xeno chloride) laser pulses. The laser energy densi...Thin metallic layers (~ 2 μm) of Ni were deposited on polycrystalline Al2O3. ZrO2 and (Ce-TZP)+Al2O3 ceramic substrates. and further irradiated with pulsed excimer (Xeno chloride) laser pulses. The laser energy density was varied from 0.21 to 0.81 J / cm2 to optimize bending strength. For ZrO2 ceramic, it was found that the strength increases from 530 to 753 MPa at 0.51 J / cm2 irradiation. For Al2O3 and (Ce-TZP)+ Al2O3 the fracture strength also increases in varying degree. The causes of strength increment were discussed.展开更多
Changes of surface morphology following XeCI excimer laser irradiation were investigated for three engineering ceramic materials (Al2O3, Al2O3-SiC nanocomposite and Si3N4). Al2O3 and AI2O3-SiC nanocomposite samples ex...Changes of surface morphology following XeCI excimer laser irradiation were investigated for three engineering ceramic materials (Al2O3, Al2O3-SiC nanocomposite and Si3N4). Al2O3 and AI2O3-SiC nanocomposite samples exhibit a smooth rapid melt layer on the surface, and the formation of the metastabfe γ-Al2Oa was observed. A silicon-rich layer on the surface was formed after laser irradiation of Si3N4. The toughness K1c of the materials was measured by the indentation fracture method. After laser irradiation, the toughness of Al2O3, Al2O3-SiC nanocomposite and Si3N4 was improved to various degrees: Al2O3-SiC nanocomposite, 60% (max.); AI203, 40% (max.); Si3N4, 12% (max.).展开更多
Wetting condition of micro/nanostructured surface has received tremendous attention due to the potential applications in commercial,industrial,and military areas.Surfaces with extreme wetting properties,e.g.,superhydr...Wetting condition of micro/nanostructured surface has received tremendous attention due to the potential applications in commercial,industrial,and military areas.Surfaces with extreme wetting properties,e.g.,superhydrophobic or superhydrophilic,are extensively employed due to their superior anti-icing,drag reduction,enhanced boiling heat transfer,self-cleaning,and anti-bacterial properties depending on solid-liquid interfacial interactions.Laser-based techniques have gained popularity in recent years to create micro/nano-structured surface owing to their high flexibility,system precision,and ease for automation.These techniques create laser induced periodic surface structures(LIPSS)or hierarchical structures on substrate material.However,micro/nanostructures alone cannot attain the desired wettability.Subsequent modification of surface chemistry is essentially needed to achieve target extreme wettability.This review paper aims to provide a comprehensive review for both laser texturing techniques and the following chemistry modification methods.Recent research progress and fundamental mechanisms of surface structure generation via different types of lasers and various chemistry modification methods are discussed.The complex combination between the laser texturing and surface chemistry modification methods to decide the final wetting condition is presented.More importantly,surface functionalities of these surfaces with extreme wetting properties are discussed.Lastly,prospects for future research are proposed and discussed.展开更多
The distribution of residual austenite in the laser hardening laver on the gray cast iron and the change in the amount of residual austenite during sliding wearing have been investigated by X-ray diffractometer.The th...The distribution of residual austenite in the laser hardening laver on the gray cast iron and the change in the amount of residual austenite during sliding wearing have been investigated by X-ray diffractometer.The thin foils of the hardening layer worn down have been observed by electron microscopy.It was revealed that two types of martensite are strain-induced by slid- ing wearing under load of 1.72 MPa on the hardening layer of residual austenite.The strain induced martensite is profitable to improve the sliding wearing resistance.展开更多
The laser melted-resolidified processing on W18Cr4V high speed tool steel has been made us- ing a 1 kW CO_2 continuous wave laser device.The microstructure of the laser melted- resolidified layer has been examined by ...The laser melted-resolidified processing on W18Cr4V high speed tool steel has been made us- ing a 1 kW CO_2 continuous wave laser device.The microstructure of the laser melted- resolidified layer has been examined by optical microscopy and transmission electron microscopy(TEM).It was characteristic of extremely fine dendrite in the laser melted- resolidified layer and δ-ferrite in bulk form in the center of dendrite.The predominant twin martensite and a little dislocation martensite existed in the dendrite.The thin plate-like M_(213)C_6 carbide precipitated coherently on the twin martensites along their twin plane.There were both austenite rich in W,V and Cr and M_6C carbide in the interdendritic regions.展开更多
The main objective of the study was the modification of the surface layer of magnesium alloy by the COlaser. The studied material was the commercial AZ91 magnesium alloy. The effectiveness of the alternations caused b...The main objective of the study was the modification of the surface layer of magnesium alloy by the COlaser. The studied material was the commercial AZ91 magnesium alloy. The effectiveness of the alternations caused by the remelting process was verified on the basis of microscopic observation and corrosion investigations, i e, recording of potentiodynamic polarization curves, electrochemical noise measurements and hydrogen evolution rate measurements. For the adopted range of the treatment parameters, favourable changes were observed in the surface layer such as the refinement of structure and more uniform arrangement of individual phases. As a consequence of those favourable structural changes the improvement of the corrosion resistance of the alloy was achieved in comparison to its non-remelted equivalent. For the treated material corrosion rates expressed as corrosion current densities were at least three times lower than the appropriate values for the untreated alloy comparing them for the same period of samples immersion in the test solution. The obtained results have confirmed the effectiveness of the applied surface treatment resulting in favourable changes in the structure and corrosion properties of the AZ91 magnesium alloy.展开更多
We report on the modification of the wettability of stainless steel by picosecond laser surface microstructuring in this paper. Compared with traditional methods, picosecond laser-induced surface modification provides...We report on the modification of the wettability of stainless steel by picosecond laser surface microstructuring in this paper. Compared with traditional methods, picosecond laser-induced surface modification provides a fast and facile method for surface modification without chemical damage and environmental pollution. As a result of treatment by 100 ps laser pulses, microstructures are fabricated on the stainless steel sample surface, contributing to the increase of the contact angle from 88° to 105°, which realizes a transformation from hydrophilicity to hydrophobicity. The morphological features of fabricated microstructures are characterized by scanning electron microscopy and optical microscopy.展开更多
基金the Australian Research Council(ARC)through the discovery grant DP210101862。
文摘Biodegradable implants from magnesium(Mg)alloys have emerged in the biomedical field especially in the orthopedic and cardiovascular stent applications owing to their low density,high specific strength,excellent machinability,good biocompatibility,and biodegradability.The primary shortcoming of Mg-based implants is their low corrosion resistance in the physiological environment,which results in premature mechanical integrity loss before adequate healing and the production of excessive hydrogen gas,which is harmful to the body tissues and negatively affects the biocompatibility of the implant.Laser surface modification has recently received attention because it can improve the surface properties such as surface chemistry,roughness,topography,corrosion resistance,wear resistance,hydrophilicity,and thus cell response to the surface of the material.The composition and microstructures including textures and phases of laser-treated surfaces depend largely on the laser processing parameters(input laser power,laser scan velocity,frequency,pulse duration,pressure,gas circulation,working time,spot size,beam focal position,and laser track overlap)and the thermophysical properties of the substrate(solubility,melting point,and boiling point).This review investigates the impacts of various laser surface modification techniques including laser surface melting,laser surface alloying,laser cladding,laser surface texturing,and laser shock peening,and highlights their significance in improving the surface properties of biodegradable Mg alloys for implant applications.Additionally,we explore how different laser process parameters affect its composition,microstructure,and surface properties in each laser surface modification technique.
基金supported by the National Natural Science Foun-dation of China(grant Nos.52275318 and 52175307)Taishan Scholars Foundation of Shandong Province(No.tsqn201812128)+1 种基金Shandong Natural Science Foundation(Nos.ZR2023JQ021 and ZR2023QE221)China Academy of Space Technology Innovation Foundation(No.CAST2022).
文摘A bonding approach based on laser surface modification was developed to address the poor bonding be-tween Si_(3)N_(4) ceramic and Cu.The bonding mechanism in Si_(3)N_(4)/Cu heterogeneous composite structure fabricated by laser modification-assisted bonding is examined by means of scanning/transmission elec-tron microscopy and thermodynamic analysis.In the bonding process under laser modification,atomic intermixing at the interface is confirmed,as a result of the enhanced diffusion assisted by the dissocia-tion of Si_(3)N_(4) ceramic by laser.The dissociating Si precipitations on the surface,as well as the formation of micro-pores interfacial structure,would be the key concept of the bonding,by which the seamless and robust heterointerfaces were created.By controlling the laser-modifying conditions,we can obtain a reli-able heterostructure via the optimization of the trade-off of the surface structure and bonding strength,as determined by the laser-modified surface prior to bonding.The maximum structure depth and S ratio at the Si_(3)N_(4) surface were produced at a laser power of 56 W,corresponding to the maximal shear strength of 15.26 MPa.It is believed that the further development of this bonding technology will advance power electronic substrate fabrication applied in high-power devices.
基金863 Program grant number: 2077AA09Z436+1 种基金Guangdong Province '211' Fund for Biomaterials and Tissue Engineering grantnumber: 50621030
文摘A PVA-GAG-COL composite scaffold is fabricated by polyvinyl alcohol （PVA）, glyeosaminoglycan （GAG） and collagen （COL）. Laser surface modification technology is used to make holes on the surface of the scaffolds. Inside and outside interconnection micro-porous structure is obtained. Bioeompatibility test of the scaffolds shows that PVA-GAG-COL scaffold can promote the adhesion and proliferation of the fibroblast. Also, fibroblast can grow normally on the scaffolds with pore diameter from 115 um to 255 um and pore distance from 500 um to 2000 um. PVA-GAG-COL scaffolds possess excellent cell biocompatibility. The porous structure is suitable for cell culture in tissue engineering.
基金Shandong Provincial Natural Science Foundation(ZR2023ME077,ZR2023MC140)National Natural Science Foundation of China(52175408)。
文摘The surface of magnesium alloy was laser-processed,and the laser-etched morphology was determined as grooves by observing the surface morphology of sheep rib bone.The wettability of different morphologies was investigated by contact angle test.Through the cell adhesion test,the effects of different morphologies on cell adhesion,growth and migration were investigated.Results show that the wetting angle of the block-shaped surface is smaller than that of the groove-shaped surface,and block-shaped surface has better hydrophilicity.Compared with the smooth surface,the block-shaped surface has better cell adhesion,and the depressions and bumps are full of cells,suggesting that the micropatterns prepared by the laser processing are conducive to the enhancement of biocompatibility.
基金Supported by the National Basic Research Program of China("973"Program,No.2010CB327800)National Natural Science Foundation of China(No.11004150)Postdoctoral Science Foundation of China(No.20090460690)
文摘Irradiated by infrared laser, the surface reducibility and adsorbability of Cu-Cr complex could be improved, owing to the interaction of photo-fragmentation and laser texturing. Analyzed by the binding energy spectra and the auger spectra, the valence states of chromium ion and copper ion were+3 and+1 after radiation respectively, which still had the reducibility to release electrons. In contrast with the near-infrared(NIR)1 064 nm and mid-infrared(MIR) 10 600 nm laser at the same average output power of 15 W, the reduced metal percentage in the Cu-Cr complex was obviously distinguished at the depth from nanometer to micron. After chemical plating, the average coating thickness and mean-square deviation of the NIR sample were 11.61 μm and 0.30 for copper layer, and 2.69 μm and 0.08 for nickel layer. The results were much better than those of the MIR sample.
文摘The surface modification of materials such as Ti-6Al-4V is necessary to improve their wear resistant properties for use in tribological applications. In this paper it is shown that a laser with low power and tungsten inert gas (TIG) can be combined together for surface modification of Ti-6Al-4V alloy, and when performed in a controlled atmosphere of pure nitrogen or a mixture of nitrogen and argon, can produce a wear-resistant surface alloy. Compared with laser processing, a cheaper surface modification process has been developed involving a shorter processing time, which is free of stringent requirements such as a vacuum system.
文摘Thin metallic layers (~ 2 μm) of Ni were deposited on polycrystalline Al2O3. ZrO2 and (Ce-TZP)+Al2O3 ceramic substrates. and further irradiated with pulsed excimer (Xeno chloride) laser pulses. The laser energy density was varied from 0.21 to 0.81 J / cm2 to optimize bending strength. For ZrO2 ceramic, it was found that the strength increases from 530 to 753 MPa at 0.51 J / cm2 irradiation. For Al2O3 and (Ce-TZP)+ Al2O3 the fracture strength also increases in varying degree. The causes of strength increment were discussed.
文摘Changes of surface morphology following XeCI excimer laser irradiation were investigated for three engineering ceramic materials (Al2O3, Al2O3-SiC nanocomposite and Si3N4). Al2O3 and AI2O3-SiC nanocomposite samples exhibit a smooth rapid melt layer on the surface, and the formation of the metastabfe γ-Al2Oa was observed. A silicon-rich layer on the surface was formed after laser irradiation of Si3N4. The toughness K1c of the materials was measured by the indentation fracture method. After laser irradiation, the toughness of Al2O3, Al2O3-SiC nanocomposite and Si3N4 was improved to various degrees: Al2O3-SiC nanocomposite, 60% (max.); AI203, 40% (max.); Si3N4, 12% (max.).
基金Project(52105175)supported by the National Natural Science Foundation of ChinaProject(BK20210235)supported by the Natural Science Foundation of Jiangsu Province,ChinaProject(JSSCBS20210121)supported by the Jiangsu Provincial Innovative and Entrepreneurial Doctor Program,China。
文摘Wetting condition of micro/nanostructured surface has received tremendous attention due to the potential applications in commercial,industrial,and military areas.Surfaces with extreme wetting properties,e.g.,superhydrophobic or superhydrophilic,are extensively employed due to their superior anti-icing,drag reduction,enhanced boiling heat transfer,self-cleaning,and anti-bacterial properties depending on solid-liquid interfacial interactions.Laser-based techniques have gained popularity in recent years to create micro/nano-structured surface owing to their high flexibility,system precision,and ease for automation.These techniques create laser induced periodic surface structures(LIPSS)or hierarchical structures on substrate material.However,micro/nanostructures alone cannot attain the desired wettability.Subsequent modification of surface chemistry is essentially needed to achieve target extreme wettability.This review paper aims to provide a comprehensive review for both laser texturing techniques and the following chemistry modification methods.Recent research progress and fundamental mechanisms of surface structure generation via different types of lasers and various chemistry modification methods are discussed.The complex combination between the laser texturing and surface chemistry modification methods to decide the final wetting condition is presented.More importantly,surface functionalities of these surfaces with extreme wetting properties are discussed.Lastly,prospects for future research are proposed and discussed.
文摘The distribution of residual austenite in the laser hardening laver on the gray cast iron and the change in the amount of residual austenite during sliding wearing have been investigated by X-ray diffractometer.The thin foils of the hardening layer worn down have been observed by electron microscopy.It was revealed that two types of martensite are strain-induced by slid- ing wearing under load of 1.72 MPa on the hardening layer of residual austenite.The strain induced martensite is profitable to improve the sliding wearing resistance.
文摘The laser melted-resolidified processing on W18Cr4V high speed tool steel has been made us- ing a 1 kW CO_2 continuous wave laser device.The microstructure of the laser melted- resolidified layer has been examined by optical microscopy and transmission electron microscopy(TEM).It was characteristic of extremely fine dendrite in the laser melted- resolidified layer and δ-ferrite in bulk form in the center of dendrite.The predominant twin martensite and a little dislocation martensite existed in the dendrite.The thin plate-like M_(213)C_6 carbide precipitated coherently on the twin martensites along their twin plane.There were both austenite rich in W,V and Cr and M_6C carbide in the interdendritic regions.
文摘The main objective of the study was the modification of the surface layer of magnesium alloy by the COlaser. The studied material was the commercial AZ91 magnesium alloy. The effectiveness of the alternations caused by the remelting process was verified on the basis of microscopic observation and corrosion investigations, i e, recording of potentiodynamic polarization curves, electrochemical noise measurements and hydrogen evolution rate measurements. For the adopted range of the treatment parameters, favourable changes were observed in the surface layer such as the refinement of structure and more uniform arrangement of individual phases. As a consequence of those favourable structural changes the improvement of the corrosion resistance of the alloy was achieved in comparison to its non-remelted equivalent. For the treated material corrosion rates expressed as corrosion current densities were at least three times lower than the appropriate values for the untreated alloy comparing them for the same period of samples immersion in the test solution. The obtained results have confirmed the effectiveness of the applied surface treatment resulting in favourable changes in the structure and corrosion properties of the AZ91 magnesium alloy.
基金financially supported by the National Natural Science Foundation of China (Grant Nos. 61178024 and 11374316)partially supported by the National Basic Research Program of China (Grant No.2011CB808103)
文摘We report on the modification of the wettability of stainless steel by picosecond laser surface microstructuring in this paper. Compared with traditional methods, picosecond laser-induced surface modification provides a fast and facile method for surface modification without chemical damage and environmental pollution. As a result of treatment by 100 ps laser pulses, microstructures are fabricated on the stainless steel sample surface, contributing to the increase of the contact angle from 88° to 105°, which realizes a transformation from hydrophilicity to hydrophobicity. The morphological features of fabricated microstructures are characterized by scanning electron microscopy and optical microscopy.
