Ni-based alloy coating on 21-4-N heat-resistant steel was prepared using CO2 laser, and the high-temperature abrasion wear was tested. The microstructure of this cladding layer and its abrasion wear behavior at high t...Ni-based alloy coating on 21-4-N heat-resistant steel was prepared using CO2 laser, and the high-temperature abrasion wear was tested. The microstructure of this cladding layer and its abrasion wear behavior at high temperature by changing compositions and temperatures were investigated by means of optical microscope and scanning electron microscope. Among the three compositions of cladding layer, i.e. Ni21+20%WC+0.5%CeO2, Ni25+20%WC+0.5%CeO2 and Ni60+20%WC+0.5%CeO2, the experimental results show that Ni21+20%WC+ 0.5%CeO2 cladding layer is made up of finer grains, and presents the best abrasion wear behavior at high temperature. The wear pattern of laser cladding layer is mainly grain abrasion at lower temperature, and it would be changed to adhesive abrasion and oxide abrasion at higher temperature.展开更多
1.IntroductionBoronizing can evidently increase thesurface hardness and wear resistance of me-tallic materials[1].It is simple in technique,not expensive and widely used on tools,diesand some other parts which are eas...1.IntroductionBoronizing can evidently increase thesurface hardness and wear resistance of me-tallic materials[1].It is simple in technique,not expensive and widely used on tools,diesand some other parts which are easy towear.However the wear mechanism andbehaviour of boronized layer are not clearwhen abraded by mixed abradants such ascoal,hard mineral etc.[2,3].Several metallic materials commonly展开更多
Mar and abrasion resistance were investigated by a progressive load scratch test and steel wool abrasion test, respectively. Two acrylic coating systems including trimethylolpropane triacrylate (TMPTA) and pentaerythr...Mar and abrasion resistance were investigated by a progressive load scratch test and steel wool abrasion test, respectively. Two acrylic coating systems including trimethylolpropane triacrylate (TMPTA) and pentaerythritol triacrylate (PETA) were prepared. A soft base layer was introduced as an intermediate layer between two different types of top layer and poly (methyl methacrylate) (PMMA) substrate to demonstrate the effect of soft base layer on mar and abrasion resistance. Abrasion damage on the coating surface was found to be less severe, when the soft base layer was incorporated into the coating systems. The reduction in scratch coefficient of friction (SCOF) and surface roughness was also observed. The results suggested that mar and abrasion resistance was greatly influenced by the presence of soft base layer, although different top layers were used. Moreover, it was found that abrasion resistance was further improved as the thicker soft base layer was applied.展开更多
A new technique was introduced that TiN permeation layer composed of diffusion and deposition layer was synthesized on the surface of Q235 steel using plasma point discharge and hollow cathode effect, and then TiB2 fi...A new technique was introduced that TiN permeation layer composed of diffusion and deposition layer was synthesized on the surface of Q235 steel using plasma point discharge and hollow cathode effect, and then TiB2 film was deposited （PVD） on newly-formed surface to create TiN/TiB2 multi-permeation layer. The thickness of this multi-permeation layer is above 10μm and the composition and hardness have graded distribution. It has metallurgical bonding with substrate and the bonding strength is high without any spallation phenomenon. In addition comparative research, between TiN/TiB2 multi-permeation layer and TiB2 film which is directly deposited （PVD） on Q235 steel substrate, on surface appearance, microhardness and friction-abrasion property was carried out. The results show that both of surface consist of uniform, compact and fine cellular structure. Surface microhardness of TiN/TiB2 multi-permeation layer is higher, reaching HV2600; but its average friction coefficient is lower, abrasion crack is shallower and wear resistance is better.展开更多
The formula of the thickness of the heat-insulating layer is deduced via heat transfer analysis,according to the principle of heat transfer in limited space.Polishing experiments are carried out using the same technol...The formula of the thickness of the heat-insulating layer is deduced via heat transfer analysis,according to the principle of heat transfer in limited space.Polishing experiments are carried out using the same technological parameters.Compared with the polishing experimental results,the heat transfer model is proved to be correct.As validated by the experimental results,polyurethane heat-insulating layer can effectively improve the service life of the ice fixed abrasive pad and alleviate the melting rate in the polishing process to improve the polishing quality proposed.The heat transfer model provides theoretical basis for research of temperature field of ice fixed abrasive polishing.展开更多
The abrasive waterjet (AWJ) is now widely used in the advanced cutting processes of polymers,metals,glass,ceramics and composite materials like thin multiple-layered material (TMM).Various research and development eff...The abrasive waterjet (AWJ) is now widely used in the advanced cutting processes of polymers,metals,glass,ceramics and composite materials like thin multiple-layered material (TMM).Various research and development efforts have recently been made to understand the science of AWJ.However,the interaction mechanism between a workpiece and high-velocity abrasive particles still remains a complicated problem.In this work,the material removal mechanisms of AWJ such as micro penetration and micro dent were experimentally investigated.In addition,a new computer simulation model considering high strain rate effect was proposed to understand the micro impact behavior of high-velocity micro-sized abrasives in AWJ cutting.展开更多
A chemical composite plating of Ni-B_(4)C was used to prepare the surface-modified zirconia toughened alumina(ZTA)ceramic particles.The ceramic preforms were prepared by the plated ZTA and sodium silicate solution bin...A chemical composite plating of Ni-B_(4)C was used to prepare the surface-modified zirconia toughened alumina(ZTA)ceramic particles.The ceramic preforms were prepared by the plated ZTA and sodium silicate solution binder,followed by casting infiltration to prepare the ZTA particles reinforced high chromium cast iron(HCCI)composites.The result reveals that a distinct interface layer forms at the ZTA/HCCI interface,which consists of phases of ZrB_(2),FeB,Fe_(2)B,and NaSiO_(4).The interfacial wettability between ZTA and HCCI is improved by the diffusion and reaction of Ni and B_(4)C.The wear test reveals that the Ni-B_(4)C plated ZTA particles can effectively improve the wear resistance of the ZTA/HCCI composite,and the wear rate of the composite is decreased to 11.6%of HCCI.展开更多
文摘Ni-based alloy coating on 21-4-N heat-resistant steel was prepared using CO2 laser, and the high-temperature abrasion wear was tested. The microstructure of this cladding layer and its abrasion wear behavior at high temperature by changing compositions and temperatures were investigated by means of optical microscope and scanning electron microscope. Among the three compositions of cladding layer, i.e. Ni21+20%WC+0.5%CeO2, Ni25+20%WC+0.5%CeO2 and Ni60+20%WC+0.5%CeO2, the experimental results show that Ni21+20%WC+ 0.5%CeO2 cladding layer is made up of finer grains, and presents the best abrasion wear behavior at high temperature. The wear pattern of laser cladding layer is mainly grain abrasion at lower temperature, and it would be changed to adhesive abrasion and oxide abrasion at higher temperature.
文摘1.IntroductionBoronizing can evidently increase thesurface hardness and wear resistance of me-tallic materials[1].It is simple in technique,not expensive and widely used on tools,diesand some other parts which are easy towear.However the wear mechanism andbehaviour of boronized layer are not clearwhen abraded by mixed abradants such ascoal,hard mineral etc.[2,3].Several metallic materials commonly
文摘Mar and abrasion resistance were investigated by a progressive load scratch test and steel wool abrasion test, respectively. Two acrylic coating systems including trimethylolpropane triacrylate (TMPTA) and pentaerythritol triacrylate (PETA) were prepared. A soft base layer was introduced as an intermediate layer between two different types of top layer and poly (methyl methacrylate) (PMMA) substrate to demonstrate the effect of soft base layer on mar and abrasion resistance. Abrasion damage on the coating surface was found to be less severe, when the soft base layer was incorporated into the coating systems. The reduction in scratch coefficient of friction (SCOF) and surface roughness was also observed. The results suggested that mar and abrasion resistance was greatly influenced by the presence of soft base layer, although different top layers were used. Moreover, it was found that abrasion resistance was further improved as the thicker soft base layer was applied.
文摘A new technique was introduced that TiN permeation layer composed of diffusion and deposition layer was synthesized on the surface of Q235 steel using plasma point discharge and hollow cathode effect, and then TiB2 film was deposited （PVD） on newly-formed surface to create TiN/TiB2 multi-permeation layer. The thickness of this multi-permeation layer is above 10μm and the composition and hardness have graded distribution. It has metallurgical bonding with substrate and the bonding strength is high without any spallation phenomenon. In addition comparative research, between TiN/TiB2 multi-permeation layer and TiB2 film which is directly deposited （PVD） on Q235 steel substrate, on surface appearance, microhardness and friction-abrasion property was carried out. The results show that both of surface consist of uniform, compact and fine cellular structure. Surface microhardness of TiN/TiB2 multi-permeation layer is higher, reaching HV2600; but its average friction coefficient is lower, abrasion crack is shallower and wear resistance is better.
基金supported by the National Natural Science Foundation of China(No.51375237)the Natural Science Foundation of Jiangsu Province(No.BK2012796)the Scientific Research Start Project of Talent Introduction of NUAA(No.1005-56YAH)
文摘The formula of the thickness of the heat-insulating layer is deduced via heat transfer analysis,according to the principle of heat transfer in limited space.Polishing experiments are carried out using the same technological parameters.Compared with the polishing experimental results,the heat transfer model is proved to be correct.As validated by the experimental results,polyurethane heat-insulating layer can effectively improve the service life of the ice fixed abrasive pad and alleviate the melting rate in the polishing process to improve the polishing quality proposed.The heat transfer model provides theoretical basis for research of temperature field of ice fixed abrasive polishing.
文摘The abrasive waterjet (AWJ) is now widely used in the advanced cutting processes of polymers,metals,glass,ceramics and composite materials like thin multiple-layered material (TMM).Various research and development efforts have recently been made to understand the science of AWJ.However,the interaction mechanism between a workpiece and high-velocity abrasive particles still remains a complicated problem.In this work,the material removal mechanisms of AWJ such as micro penetration and micro dent were experimentally investigated.In addition,a new computer simulation model considering high strain rate effect was proposed to understand the micro impact behavior of high-velocity micro-sized abrasives in AWJ cutting.
基金financially supported by the National Natural Science Foundation of China(52005217)the University Research Platform and Research Projects of Guangdong Education Department(2022ZDZX3003)+2 种基金Basic and Applied Basic Research Fund Project of Guangdong Province in China(2022A1515010091,2021A1515010523,and 2020A1515110020)Basic Scientific Research Projects of Central Universities(No.21620344)Jinan University Open Fund for Advanced Materials(JNIWRM2021004)。
文摘A chemical composite plating of Ni-B_(4)C was used to prepare the surface-modified zirconia toughened alumina(ZTA)ceramic particles.The ceramic preforms were prepared by the plated ZTA and sodium silicate solution binder,followed by casting infiltration to prepare the ZTA particles reinforced high chromium cast iron(HCCI)composites.The result reveals that a distinct interface layer forms at the ZTA/HCCI interface,which consists of phases of ZrB_(2),FeB,Fe_(2)B,and NaSiO_(4).The interfacial wettability between ZTA and HCCI is improved by the diffusion and reaction of Ni and B_(4)C.The wear test reveals that the Ni-B_(4)C plated ZTA particles can effectively improve the wear resistance of the ZTA/HCCI composite,and the wear rate of the composite is decreased to 11.6%of HCCI.
