Zr/WC composite coating was prepared on the surface of Cr12MoV steel by electric spark deposition technology to change its surface properties. The surface and worn surface morphology of the coating were observed using...Zr/WC composite coating was prepared on the surface of Cr12MoV steel by electric spark deposition technology to change its surface properties. The surface and worn surface morphology of the coating were observed using scanning electron microscope. Dry friction and wear tests of the coatings were carried out at room temperature. The results show that the coating is continuous and uniform, and the thickness was about 50-60 μm. The microhardness of the coating surface was highest at 1140 HV_(200g), which was significantly higher than that of the substrate. The ear tests results show that the wear weight loss, wear volume and wear rate follow the following rules: Cr12MoV>WC coating> Zr/WC composite coating.展开更多
An experimental study has been carried out to investigate the influence of heat treatment at 300 ℃,450 ℃,550 ℃,650 ℃ and 800 ℃ on the microstructure and sliding wear behavior of Fe Al/WC intermetallic composite c...An experimental study has been carried out to investigate the influence of heat treatment at 300 ℃,450 ℃,550 ℃,650 ℃ and 800 ℃ on the microstructure and sliding wear behavior of Fe Al/WC intermetallic composite coatings produced by high velocity arc spraying (HVAS) and cored wires. The result shows, the main phases in both as sprayed and heat treated Fe Al/WC composite coatings are iron aluminide intermetallics (Fe 3Al+FeAl) and α as well as a little oxide (Al 2O 3) and carbides (WC, W 2C, Fe 2W 2C and Fe 6W 6C). After heat treated at 450-650 ℃, dispersion strengthening of Fe 2W 2C and Fe 6W 6C will lead to a rise in microhardness of the coatings. The microhardness is likely to be the most important factor which influences the sliding wear behavior of the coatings. Increasing the microhardness through heat treatment will improve the sliding wear resistance of the Fe Al/WC composite coatings.展开更多
The WC-Co composite coatings bonded tightly to steel substrate have been made by vacuum fusion sinter （VFS）. The concentration distribution of some components were measured by the electron probe, and the microstruct...The WC-Co composite coatings bonded tightly to steel substrate have been made by vacuum fusion sinter （VFS）. The concentration distribution of some components were measured by the electron probe, and the microstructure and morphology of VFS coatings were observed and analyzed by SEM, X-ray diffractometer and microhardness tester. Diffusion coefficient of every element was calculated by using the experimental results. The influence of the interracial diffusion on the microstructure, Vickers hardness and interracial bond strength of the VFS coatings was studied in detail. The experimental results show that there is a metallurgical bond area between the VFS WC-Co coatings and the steel substrate. The VFS coatings are characterized by the gradient hardness of the interface and the high bond strength to the steel substate, both of which are beneficial to the improvement of the wear resistance and corrosion resistance.展开更多
The Fe40Al-xWC(x=0,10,12,15)coatings with dense structure were successfully deposited by high-velocity oxygen fuel (HVOF)spraying of a mixture of Fe,Al and WC powders.The objective of the present work is to provide in...The Fe40Al-xWC(x=0,10,12,15)coatings with dense structure were successfully deposited by high-velocity oxygen fuel (HVOF)spraying of a mixture of Fe,Al and WC powders.The objective of the present work is to provide insight into the oxidation behavior of the as-deposited coatings at 650℃under 0.1 MPa flowing pure O2.The present results show differences in the oxidation behavior of Fe40Al coating and Fe40Al-xWC composite coatings.The irregular Fe2O3 layer is seen on the top surface of the composite coatings.Fe40Al coating and Fe40Al-15WC composite coating both suffer a catastrophic corrosion due to the formation of a porous structure during 24 h of oxidation.However,Fe40Al-10WC and Fe40Al-12WC composite coatings show a good oxidation resistance behavior due to their dense structure.展开更多
目的提高Ni-P/nano-WC复合刷镀层的性能。方法利用电刷镀技术将Ni-P与nano-WC粉末共同沉积在40Cr基体表面形成纳米颗粒增强的复合镀层,再利用电接触技术对Ni-P/nano-WC复合镀层进行二次强化。利用光学显微镜、场发射扫描电子显微镜(FES...目的提高Ni-P/nano-WC复合刷镀层的性能。方法利用电刷镀技术将Ni-P与nano-WC粉末共同沉积在40Cr基体表面形成纳米颗粒增强的复合镀层,再利用电接触技术对Ni-P/nano-WC复合镀层进行二次强化。利用光学显微镜、场发射扫描电子显微镜(FESEM)、X射线衍射分析(XRD)、能谱分析(EDS)和显微硬度测量等手段,分析电接触强化处理对Ni-P/nano-WC复合镀层的影响。同时利用滚动摩擦试验分析电接触强化前后复合镀层耐磨性的变化情况。结果电接触强化处理后,Ni-P/nano-WC复合刷镀层的孔隙和裂纹减少,复合镀层与基体之间的界面在高温和高压的作用下发生焊合。XRD分析显示复合镀层的晶粒细化,镀层的晶粒尺寸由35.35 nm下降至26.28 nm。随着接触电流的加大,复合镀层的硬度也在逐步加大。经过20 k A电流的强化,复合镀层平均硬度由637HV0.1增加到885HV0.1,镀层硬度分布更加均匀;4 h的滚动摩损表明,随着接触电流的加大,试样的质量损失逐步减小,经20 k A接触电流强化后的Ni-P/nano-WC复合镀层质量损失为503 mg,比未经电接触强化的Ni-P/nano-WC复合镀层低40%。结论电接触强化技术能有效改善Ni-P/nano-WC复合镀层的微观组织与性能,将镀层界面由机械结合变为冶金结合,同时提高镀层的耐磨性能。展开更多
基金supported by Key Projects of Strategic International Scientific and Technological Innovation Cooperation(Grant No.2016YFE0201300)
文摘Zr/WC composite coating was prepared on the surface of Cr12MoV steel by electric spark deposition technology to change its surface properties. The surface and worn surface morphology of the coating were observed using scanning electron microscope. Dry friction and wear tests of the coatings were carried out at room temperature. The results show that the coating is continuous and uniform, and the thickness was about 50-60 μm. The microhardness of the coating surface was highest at 1140 HV_(200g), which was significantly higher than that of the substrate. The ear tests results show that the wear weight loss, wear volume and wear rate follow the following rules: Cr12MoV>WC coating> Zr/WC composite coating.
文摘An experimental study has been carried out to investigate the influence of heat treatment at 300 ℃,450 ℃,550 ℃,650 ℃ and 800 ℃ on the microstructure and sliding wear behavior of Fe Al/WC intermetallic composite coatings produced by high velocity arc spraying (HVAS) and cored wires. The result shows, the main phases in both as sprayed and heat treated Fe Al/WC composite coatings are iron aluminide intermetallics (Fe 3Al+FeAl) and α as well as a little oxide (Al 2O 3) and carbides (WC, W 2C, Fe 2W 2C and Fe 6W 6C). After heat treated at 450-650 ℃, dispersion strengthening of Fe 2W 2C and Fe 6W 6C will lead to a rise in microhardness of the coatings. The microhardness is likely to be the most important factor which influences the sliding wear behavior of the coatings. Increasing the microhardness through heat treatment will improve the sliding wear resistance of the Fe Al/WC composite coatings.
文摘The WC-Co composite coatings bonded tightly to steel substrate have been made by vacuum fusion sinter （VFS）. The concentration distribution of some components were measured by the electron probe, and the microstructure and morphology of VFS coatings were observed and analyzed by SEM, X-ray diffractometer and microhardness tester. Diffusion coefficient of every element was calculated by using the experimental results. The influence of the interracial diffusion on the microstructure, Vickers hardness and interracial bond strength of the VFS coatings was studied in detail. The experimental results show that there is a metallurgical bond area between the VFS WC-Co coatings and the steel substrate. The VFS coatings are characterized by the gradient hardness of the interface and the high bond strength to the steel substate, both of which are beneficial to the improvement of the wear resistance and corrosion resistance.
基金Project(209069)supported by the Key Research Program of Ministry of Education of ChinaProjects(2008GZC00652007GZC0611)supported by the Natural Science Foundation of Jiangxi Province,China
文摘The Fe40Al-xWC(x=0,10,12,15)coatings with dense structure were successfully deposited by high-velocity oxygen fuel (HVOF)spraying of a mixture of Fe,Al and WC powders.The objective of the present work is to provide insight into the oxidation behavior of the as-deposited coatings at 650℃under 0.1 MPa flowing pure O2.The present results show differences in the oxidation behavior of Fe40Al coating and Fe40Al-xWC composite coatings.The irregular Fe2O3 layer is seen on the top surface of the composite coatings.Fe40Al coating and Fe40Al-15WC composite coating both suffer a catastrophic corrosion due to the formation of a porous structure during 24 h of oxidation.However,Fe40Al-10WC and Fe40Al-12WC composite coatings show a good oxidation resistance behavior due to their dense structure.
文摘目的提高Ni-P/nano-WC复合刷镀层的性能。方法利用电刷镀技术将Ni-P与nano-WC粉末共同沉积在40Cr基体表面形成纳米颗粒增强的复合镀层,再利用电接触技术对Ni-P/nano-WC复合镀层进行二次强化。利用光学显微镜、场发射扫描电子显微镜(FESEM)、X射线衍射分析(XRD)、能谱分析(EDS)和显微硬度测量等手段,分析电接触强化处理对Ni-P/nano-WC复合镀层的影响。同时利用滚动摩擦试验分析电接触强化前后复合镀层耐磨性的变化情况。结果电接触强化处理后,Ni-P/nano-WC复合刷镀层的孔隙和裂纹减少,复合镀层与基体之间的界面在高温和高压的作用下发生焊合。XRD分析显示复合镀层的晶粒细化,镀层的晶粒尺寸由35.35 nm下降至26.28 nm。随着接触电流的加大,复合镀层的硬度也在逐步加大。经过20 k A电流的强化,复合镀层平均硬度由637HV0.1增加到885HV0.1,镀层硬度分布更加均匀;4 h的滚动摩损表明,随着接触电流的加大,试样的质量损失逐步减小,经20 k A接触电流强化后的Ni-P/nano-WC复合镀层质量损失为503 mg,比未经电接触强化的Ni-P/nano-WC复合镀层低40%。结论电接触强化技术能有效改善Ni-P/nano-WC复合镀层的微观组织与性能,将镀层界面由机械结合变为冶金结合,同时提高镀层的耐磨性能。
