Creation of precipitation hardened surface ceramics layer aiming to develop innovative steels with high wear resistance

为了获得纳米析出物强化的表面陶瓷层，对纯Fe和含有少量氮化物形成元素的Fe-M二元合金进行了气体氮化处理，并对表面层的晶体结构、生长速率和硬度进行了研究。纳米压痕测试表明，纯铁表面γ'层的硬度远高于γ'层下铁素体基体的硬度。Cr、V或Al的加入显著提高了氮化处理后铁素体的硬度，而合金化对化合物层硬度的影响相对较小。这些结果意味着通过纳米尺寸的氮化物的沉淀硬化对于硬化化合物层不是那么有效。

In order to create surface ceramics layer hardened by nano-sized precipitate, pure Fe and Fe-M binary alloys containing small amount of nitride forming elements were gaseous nitrided and crystal structure, growth rate and hardness of surface layer wereinvestigated. Nano-indentation measurements revealed that hardness of γ' layer on the surface of pure Fe is much higher than those in ferrite matrix beneath γ'. On the other hand, hardness of ferrite after nitriding treatment is significantly increased by the addition of Cr, V or Al, while alloying effect on hardness of compound layer is relatively small. Those results imply that precipitation hardening by nano-sized nitrides is not so effective to harden the compound layer.