Cr_(3)C_(2)晶粒度对HVOF喷涂Cr_(3)C_(2)-25NiCr涂层组织及其耐磨粒磨损性能的影响

Effect of Cr_(3)C_(2) Grain Size on Microstructure and Abrasive Wear Performance of HVOF Sprayed Cr_(3)C_(2)-25NiCr Coating

分别采用费氏粒度为0.8μm、3.0μm、5.0μm的碳化铬(分子式为Cr_(3)C_(2))原料,通过团聚烧结工艺制备Cr_(3)C_(2)-25NiCr热喷涂粉末。运用超音速火焰喷涂(HVOF)技术制备Cr_(3)C_(2)-25NiCr涂层,并测试了粉末沉积率;采用显微硬度计、金相显微镜和扫描电镜(SEM),分析比较不同涂层的显微硬度、孔隙率和显微组织,并利用干砂橡胶轮磨粒磨损试验机测试了涂层的耐磨损性能。结果表明:碳化铬晶粒度不同,对粉末沉积率和涂层显微硬度的影响不大,但对涂层孔隙率和耐磨粒磨损性能的影响较大;在碳化铬晶粒度为3.0μm时,制备的喷涂粉末沉积率为45.6%,涂层孔隙率为0.23%,涂层显微硬度为965.8 HV0.3,磨损失重为0.075 g/30 min,相应的涂层在3种Cr_(3)C_(2)-25NiCr涂层中具有最佳的综合性能。

In this paper,three type of Cr_(3)C_(2)-25NiCr powders were prepared by agglomerated and sintered with 0.8μm,3.0μm and 5.0μm chromium carbide respectively.The coating was prepared using these powders by high velocity oxygen-fuel spraying(HVOF)system and the deposition efficiency was tested during the spraying.The influences of Cr_(3)C_(2) grain size on the microhardness,porosity and microstructure of Cr_(3)C_(2)-25NiCr coating were analyzed by microhardness tester,metallographic microscope and SEM and the abrasive resistance of the coatings were tested by testing machine with rubber wheel.The results indicate that different grain sizes of chromium carbide has little effect on powder deposition efficiency and microhardness,however,it has great influence on the porosity and abrasive wear properties of the coating.When the grain size of chromium carbide is 3.0μm,the deposition efficiency of the powder is 45.6%,the porosity of the coating is 0.23%,the microhardness of the coating is 965.8 HV0.3,and the wear weight loss is 0.075 g/30 min.The coating has the best comprehensive properties.