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本工作试验研究了用于机械,尤其是石油化工机械中的具有耐磨、耐蚀和耐热等多功能的陶瓷涂层。以氧化铬为研究对象,采用等离子喷涂技术,研究解决热喷涂陶瓷涂层中的三个主要问题,即涂层中的残余应力、微孔洞和层间界面的弱结合。为此,系统研究了喷涂工艺参数波动、涂层结构和添加剂对氧化铬陶瓷涂层组织和性能的影响及其相互关系;涂层的热震、磨损和腐蚀失效规律和机制;建立了陶瓷涂层抗热震失效寿命的表达式。结果表明,影响涂层性能最重要的工艺参数为电弧电流,其次为涂层厚度。从基体到陶瓷层,通过涂层成分逐渐变化可以制备梯度涂层,并且多层复合涂层的综合性能优于双层涂层,其中,四层阶梯复合涂层的综合性能最佳,其次是五层梯度涂层。在氧化铬材料中,加入3.0％氧化铈,可降低涂层中的孔隙率和孔洞尺寸,从而提高氧化铬涂层的综合性能;陶瓷涂层热震失效的本质为热疲劳失效。在滑动磨损条件下,涂层的磨损失效主要是循环接触应力导致的疲劳磨损。涂层的腐蚀失效是陶瓷层自身的化学腐蚀和粘结结层/基体界面的电化学腐蚀。试验结果证实了涂层热震失效寿命定量表达式的有效性和适用性。首先提出并定义的临界热震温差范围可作为评价涂层抗热冲击性能的指标和使用依据。
This work has studied the multi-functional ceramic coatings used in machinery, especially in petrochemical machinery, which are resistant to wear, corrosion and heat. Taking chromium oxide as the research object, plasma spraying technology is used to solve three major problems in thermal sprayed ceramic coatings, namely residual stress in coating, weak combination of micropores and interface between layers. Therefore, the influence of the parameters of spray process, the influence of coating structure and additive on the microstructure and properties of chromium oxide ceramic coatings and the relationship between them were systematically studied. The thermal shock, wear and corrosion failure rules and mechanisms of the coatings were also systematically studied. Layer thermal shock failure life expression. The results show that the most important parameters affecting the performance of the coating arc current, followed by the thickness of the coating. Gradient coatings can be prepared by changing the coating composition gradually from the matrix to the ceramic layer, and the comprehensive performance of the multi-layer composite coating is better than the double coating. Among them, the four-layer composite coating has the best overall performance, followed by Five gradient coating. The addition of 3.0% cerium oxide to the chromium oxide material can reduce the porosity and pore size of the coating, thereby improving the overall performance of the chromium oxide coating; the thermal shock failure of the ceramic coating is thermal fatigue failure. Under the condition of sliding wear, the abrasion failure of the coating is mainly the fatigue wear caused by cyclic contact stress. The corrosion failure of the coating is the chemical erosion of the ceramic layer itself and the electrochemical corrosion of the bonding layer / matrix interface. The test results confirm the validity and applicability of quantitative expressions of thermal shock failure life of coatings. First proposed and defined the critical temperature range of thermal shock can be used as an evaluation of the thermal shock resistance of the coating performance indicators and the use of basis.