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铸铁等离子熔覆铁基合金耐磨涂层

Wear-resistant coating of Fe-based alloy by plasma cladding on cast iron

  • 摘要: 利用等离子熔覆技术,选择合适的工艺参数,在硼铸铁基体上熔覆铁基合金粉末制备具有冶金结合的耐磨涂层。采用金相显微镜、X射线衍射仪、扫描电镜研究了涂层的组织,利用显微硬度计测试了涂层的显微硬度,通过环-块磨损试验评估了涂层的耐磨性。结果表明,硼铸铁等离子熔覆铁基合金涂层组织主要由(Cr,Fe)7C3,α-(Fe,Cr)和Fe3C相组成;涂层的显微硬度可达600~1200 HV 0.2;在干滑动磨损条件下,涂层的耐磨性约是基体试样的5倍。涂层中高硬度的(Cr,Fe)7C3及Fe3C相的抗磨骨架作用,大量Cr,Si原子溶入基体引起的过饱和固溶强化作用,涂层快速加热及快速凝固产生的细晶强化作用是涂层耐磨性提高的主要原因。

     

    Abstract: By plasma cladding technology a wear-resistant coating with metallurgical bonding to substrate was prepared on boron cast iron with Fe-based alloy powder.The microstructure of the bondng coating was investigated by optical microscope (OM), scanning electron microscope (SEM), X-ray diffractometer (XRD).The microhardness was tested by microhardness tester.The wear resistance performance of the coating was evaluated on a MM-200 block-on-wheel sliding wear tester.The results show that the coating has a microstructure consisting of primary phase (Cr,Fe)7C3, α-(Fe,Cr)and Fe3C, its microhardness varies from 600 HV0.2 to 1200 HV0.2.The relative wear resistance of the coating is about 5 times higher than that of boron cast iron substrate under dry sliding wear test conditions, which results from the presence of hard, wear-resistant primary phase (Cr,Fe)7C3 and Fe3C in coating, the solid solution strengthening by large amount of Cr and Si supersaturated in α solid solution, and from the grain size strengthening by rapidly heating and solidification of the coating.

     

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