基于干冰微粒喷射工艺热-力-气耦合效应的热喷涂制备Cr2O3基耐磨涂层的研究

Thermal-sprayed Cr2O3 coatings which are machinable could greatly improve the wear resistance of the mechanical equipments. The anti-wear properties of Cr2O3 coatings are significantly affected by microstructure characteristics (such as microcracks, porosity) and additives, etc. The porosity reduction and the improvement of the interfacial bonding strength are the main ways to improve the wear resistance of Cr2O3 coatings. This research project is to prepare micro- or nano- structured, gradient-structured and rare earth oxide doped Cr2O3 coatings by thermal spraying (atmospheric plasma spraying APS and high-velocity oxygen-fuel HVOF) coupled with dry-ice blasting, from micro- and nano- structured powders. The effects of dry-ice blasting on the macropores and microcracks of Cr2O3 coatings would be investigated systematically as well as on the spreading behavior of the micro- and nano- structured molten particles and the distribution of the residual stress. The cooling-mechanical-sublimation mechanisms of dry-ice blasting on the gradient-structured Cr2O3 coatings would be further clarified as well as the ‘self-sealing’ effect of the additives in the preparation of Cr2O3 coatings. The relationship between the microstructure, interfacial bonding strength and residual stress distribution could be established to achieve the design and preparation of Cr2O3-based coatings with high wear resistance. It is envisaged that the success of the present project can promote to form a new coupling processing method and theory for anti-wear Cr2O3-based coatings and consequently extend considerably their reliable applications in the key components of high-end equipments.

采用热喷涂技术制备的可切削加工的Cr2O3涂层可以大幅度提高机械设备表面的耐磨性能。Cr2O3涂层的摩擦磨损性能受微结构（如微裂纹、孔隙率）和添加剂等的显著影响，减少涂层中的孔隙和提高结合强度是提高其耐磨性的主要途径。本项目拟通过热喷涂（等离子喷涂APS和超音速火焰喷涂HVOF）耦合干冰微粒喷射这一新工艺制备纳、微米结构、梯度结构以及稀土氧化物等掺杂Cr2O3涂层体系，系统研究干冰微粒喷射对纳、微米结构Cr2O3熔融颗粒铺展行为的影响机制以及对涂层大孔隙和网状微裂纹的调控机制，进一步阐明干冰微粒喷射的热-力-气三种特性对梯度结构涂层残余应力的作用机制以及添加物在Cr2O3涂层制备过程中的‘自封孔’机理，建立微结构、界面结合强度和残余应力分布状态与Cr2O3涂层摩擦磨损性能之间的关系模型，以实现高耐磨性Cr2O3基涂层的设计与制备，进一步推广其在重大装备关键零部件上的可靠应用。

采用热喷涂技术制备的可切削加工的Cr2O3涂层可以大幅度提高机械设备表面的耐磨性能。Cr2O3涂层的摩擦磨损性能受微结构（如微裂纹、孔隙率）和添加剂等的显著影响，减少涂层中的孔隙和提高结合强度是提高其耐磨性的主要途径。本项目通过等离子喷涂APS耦合干冰微粒喷射这一新工艺制备了纳、微米结构以及稀土氧化物掺杂和金属/陶瓷共掺杂Cr2O3涂层体系，系统研究了干冰微粒喷射对纳、微米结构Cr2O3熔融颗粒铺展行为的影响机制以及对涂层大孔隙和网状微裂纹的调控机制，进一步阐明了干冰微粒喷射的热-力-气三种特性对Cr2O3基涂层的作用机制以及添加物在Cr2O3涂层制备过程中的‘自封孔’机理，建立了微结构、界面结合强度等与Cr2O3涂层摩擦磨损性能之间的关系模型，可以为高耐磨性Cr2O3基涂层的设计与制备提供理论指导，进一步可以推广其在重大装备关键零部件上的可靠应用。