摘要本研究采用等离子喷涂沉积了 AlCoCrFeNiTi/NiCrBSi 复合涂层，并研究了喷涂 态涂层的微观组织结构、显微硬度、结合强度以及摩擦磨损性能。

研究发现，AlCoCrFeNiTi/NiCrBSi 复合涂层表面呈粗糙状态，大部分粒子熔化较 好。AlCoCrFeNiTi/NiCrBSi 涂层与基体的结合方式为机械结合，涂层内部存在不规则 孔隙、粒子间未结合界面等孔隙。喷涂态涂层中 NiCrBSi 粒子内部存在第二相析出物（Cr 的碳化物、硼化物、硼碳化物）。 研究表明，从基体到涂层，显微硬度整体上呈上升趋势。基体硬度约为 173HV，

基体/涂层界面硬度为 420HV，涂层内部的最大硬度为 710HV。AlCoCrFeNiTi/NiCrBSi 涂层的最大抗拉强度为 56MPa。25℃时磨损表面存在着裂纹和剥落坑，500℃时磨痕 表面存在着许多断断续续的犁沟，700℃时，涂层磨损表面形成了一层氧化膜，900℃ 时涂层磨损表面有脱落的粒子，且存在少量大的剥落坑。摩擦系数的变化分为两个阶 段，即磨损的初始“跑合阶段”和稳定磨损阶段。室温下涂层的磨损体积为 0。098mm3， 当温度从 25℃到 500℃时，涂层的磨损体积增加。涂层在 900℃的磨损体积（0。026mm3） 为基体的磨损体积（0。53mm3）的 1/20。80632

毕业论文关键词：AlCoCrFeNiTi/NiCrBSi 复合涂层；显微组织；显微硬度；结合强度；摩 擦磨损

Abstract An AlCoCrFeNiTi/NiCrBSi coating was deposited by plasma spraying, and the microstructure, microhardness, bonding strength and friction and wear properties of the coating were studied。

It is found that the surface of AlCoCrFeNiTi/NiCrBSi composite coating was rough, and most of the particles were melted。 The bonding between the coating and the substrate was mechanical bonding。 And there are pores with irregular shape and interlamellar gaps in the coating。 The second phase (carbides, borides and boron-carbide of Cr) precipitated from the NiCrBSi splats in the coating。

The results show that the microhardness increased from the substrate to the coating surface。 The microhardness of the substrate was about 173HV and that of the substrate/coating interface was 420HV。 The maximum microhardness of the coating was 710HV。 And the result shows that the maximum tensile strength of the coating was 56MPa。 For the wear test at 25oC, there existed micro cracks and spalling pits on the wear surface。 While at 500oC, the uncontinuous grooves were distributed on the wear surface。 At 700oC, wear surface of the coating was covered by an oxide film。 At 900oC, there were a few large spalling pits on the wear surface。 The variation of friction coefficient was pided into two stages: the initial “running in stage” of wear and friction and the stable wear stage。 The wear volume of the coating at room temperature was 0。098mm3。 When the temperature increased from 25oC to 500oC, the wear volume of the coating increased。 In addition, the wear volume (0。026mm3) of the coating at 900oC was 1/20 of that of the substrate (0。53mm3)。

Keywords: AlCoCrFeNiTi/NiCrBSi composite coating; microstructure; microhardness; bonding strength; friction and wear

目 录

第一章 绪论 1

1。1 选题背景和意义 1

1。2 等离子喷涂的原理、特点及应用 2

1。3 高熵合金的概念、特点及研究进展 4

1。4 NiCrBSi 材料的特点及应用 5

1。5 本课题主要研究内容与意义