原位合成ZrO2/MgO膜层及自修复裂纹研究

In-situ synthesis of ZrO2/MgO coating and self-repairing cracks

摘要:

微弧氧化熔融冷却成膜过程出现的裂纹将影响膜层的强韧性和磨损性能。本文利用ZrO₂自身的强韧性,采用原位合成制备具有自修复裂纹作用的ZrO₂/MgO膜层,研究原位合成的ZrO₂对膜层磨损性能的影响。研究发现,微弧氧化原位合成ZrO₂在高温放电通道发生相变产生体积膨胀氧化锆界面萌生微裂纹,抑制了成膜过程裂纹扩展从而实现自修复膜层裂纹的作用。通过控制锆源含量可以实现了对膜层中ZrO₂含量的调控,膜层中原位ZrO₂含量为32%,ZrO₂/MgO膜层裂纹呈现细小分散化,裂纹密度较传统膜层下降63.4%,摩擦系数减小53.4%,磨损量降低66.7%。研究认为,原位合成的ZrO₂在膜层制备过程的自修复裂纹和耐磨性的提高,可以降低摩擦系数和磨损量,改善ZrO₂/MgO膜层表面磨损性能。

Abstract:

The cracks will impact the toughness and wear properties in the coating formation process of micro-arc oxidation melting and cooling. This paper uses the ZrO₂ strength and toughness to prepare ZrO₂/MgO coating with self-repairing cracks, and investigates the effect of in-situ ZrO₂ on the wear properties of the coating. The research found that the in-situ synthesis ZrO₂ by micro-arc oxidation undergoes phase transition in the high-temperature discharge channel to generate volume expansion and micro-cracks initiation at the interface of zirconia, which inhibits the crack propagation during the coating formation process and realizes the role of self-repairing coating cracks.The ZrO₂ content in the coating can be regulated by controlling the content of the zirconium source, the in-situ ZrO₂ content in the coating is 32%, the cracks of the ZrO₂/MgO coating are finely dispersed, and the crack density is 63.4% lower than that of the traditional coating, the friction coefficient is reduced by 53.4%, the amount of wear descended by 66.7%. Research thinks, the in-situ synthesized ZrO2 self-repairing cracks and improvement of wear resistance during the coating preparation process, which can reduce the friction coefficient and mass loss, and improve the surface wear properties of the ZrO₂/MgO coating.