大气等离子喷涂镍铬涂层界面缺陷形成分析及工艺调控研究

Analysis of Interfacial Defect Formation and Process Control of Ni-Cr Coatings by Atmospheric Plasma Spraying

摘要:

涂层/基体界面污染率是考核涂层质量的重要指标。针对某新型发动机机匣内壁镍铬涂层界面存在的严重污染问题，首先利用显微组织分析及物相分析手段确定了界面污染物主要成分为Al₂O₃。然后，进行多因素对比试验重现了界面污染现象，确定了污染物来源为喷砂过程中滞留在基体表面的砂砾，并结合零件尺寸及外形开展了喷砂工艺优化研究。研究结果表明：具有较大动能的砂砾会嵌入硬度较低的基体中，造成界面污染；减少砂粒撞击动能及增加清理时间，可有效地减小涂层/基体界面污染率。

Abstract:

The pollution ratio of the coating/substrate interface is an important metric to assess the quality of the coating. To address the serious pollution of the Ni-Cr coating interface on the inner wall of a new engine casing manufactured by Liyang Company， the major component of the interfacial pollutant was firstly determined to be Al₂O₃ by microstructure analysis and phase analysis. Then， multi-factor comparative test was used to reproduce the phenomenon of interface pollution， and the source of pollutants was determined to be the sand remaining on the substrate surface during the sand blasting process， and the optimization of the sand blasting process was carried out based on the size and shape of the parts. Results show that sand grits with higher kinetic energy will embed into the substrate with lower hardness and cause interfacial contamination. Reducing the kinetic impact energy of the sand grits and increasing the cleaning time can effectively reduce the contamination rate at the coating/substrate interface.