悬浮液等离子喷涂与常规等离子喷涂纳米结构陶瓷涂层的研究

以蛇纹石,矿物质羟基硅酸镁Mg6(Si4O10)(OH)8,为主成分的自修复剂对金属磨损表面的修复作用,在我国已得到较为广泛关注和认同。文中以在内燃机车柴油机缸套内表面生成的自修复层为例,通过SEM,XRD,XPS,AES,Laser Raman,HRTEM,STEM和纳米硬度计等表面分析和测量手段,深入观察和分析了磨损表面自修复层的生成机理。结果表明:蛇纹石的高化学活性使氧原子、氧离子和自由水从表面向内部强扩散,铁基金属的合金成分渗碳体(Fe3C)被氧化。这是有别于高温内氧化的一种特殊的内氧化过程,对磨损表面生成自修复层有决定性的作用。进而,摩擦副的相对往复运动诱发内氧化组织的形变细化和形变强化,形成性能优异的自修复保护层。

Research on Nanostructured Ceramic Coatings by Suspension Plasma Spraying and Conventional Plasma Spraying

The restoring effect on worn metal surfaces from auto-reconditionging agent containing serpentine, mineral magnesium silicate hydroxide of empirical formula Mg_6(Si_4O_(10))(OH)_8, as a main component has been widely interested and recognized by specialists in the fields of both science and technology in our country. As an example, the genaration mechanisms of reconditioning layer on cylinder bore of a locomotive diesel engine were observed and investigated in detail through various means of surface analysis and measurememt including SEM, XRD, XPS, AES, Laser Raman, HRTEM, STEM, and Nanoindentor. The results indicate that the strongly diffusing-in of oxygen atom,ion and free water from the metal surface by high chemical activity of serpentine results in oxidation of alloy component (Fe_3C) of Fe-based metal. This is a special internal oxidation process quite different from the high temperature internal oxidation which plays a crucial role to form the reconditioning layer. Sequentially, the deformed refinement and strengthening of the internal oxidation structure under reciprocating movement of the fiction pair bring on the reconditioning protective layer with excellent behaviors.