激光合金化熔覆制备耐磨陶瓷梯度涂层

PREPARATION OF WEAR-RESISTANT GRADED METAL-CERAMIC COATING BY LASER-ALLOYING

利用预涂敷与激光重熔方法制备陶瓷梯度涂层，并对涂层的冶金结构、组成、硬度、以及耐磨性进行分析。结果表明：该涂层内陶瓷硬质相体积百分比沿基体到表面方向呈梯度变化，过渡层为具有良好韧性的固溶体。涂层结构均匀，和基体结合良好，无气孔和裂纹。厚度为０．４－０．８ｍｍ，表层硬度达ＨＶ_（０．２）１１００。与普通激光涂层比较，涂层内部的硬度随着成分组成的变化而平缓变化，既提高了涂层与基体的结合强度又提高了表面的耐磨性，同时，避免裂纹的产生。

A wear-resistant graded layer on low carbon steel A3 substrate was made of repeated coating and CO_2 laser-remelting Ni35 alloy powder together with Ni-clad WC grains. The metallurgical structure, composition, hardness and abrasive wear resistance of the layer were examined. The volume fraction of hard ceramic phases, mainly WC grains, varied gradually from surface to subatrate. The layer, 0.4-0.8 mm in thickness, had a uniform structure, good toughness, surface hardness about HV_0.21100, excellent bonding with substrate and free from pore and crack.