【摘要】 采用X射线衍射仪、扫描电镜和显微硬度计研究了45#钢表面激光熔覆纳米Al2O3改性Al2O3+13%TiO2(质量分数)陶瓷涂层的相组成、微观结构和显微硬度,同时对涂层的磨损特性进行了考察。结果表明,激光重熔区亚稳相γ Al2O3转变成稳定相α Al2O3,熔覆层由粗颗粒α Al2O3和TiO2以及纳米α Al2O颗粒组成,在激光的作用下,等离子喷涂层的片层状结构得以消除;纳米Al2O3颗粒仍然保持在纳米尺度,填充在涂层的大颗粒之间,使涂层致密化程度得以提高,因此纳米Al2O3改性涂层的显微硬度较高,且其耐磨性能明显优于等离子喷涂层。更多还原

【Abstract】 The phase constitution, microstructure and microhardness of Al₂O₃+13%TiO₂（mass fraction） composite ceramic coatings laser-claded by Al₂O₃ nano-particles on 45^# steel were investigated using X-ray diffractometry, scanning electron microscopy and microhardness measurement. Also, wear behavior of the coatings was studied. The results show that the metastable γ-Al₂O₃ phases in the cladding area transfer into stable phase of α-Al₂O₃, composite ceramic coating consists of α-Al₂O₃ and TiO₂, and lamellar structure of plasma-sprayed coatings is eliminated after the laser-cladding. A large number of Al₂O₃ nano-particles are found among the large particles of the ceramic coating and play an important role in improving the density of the ceramic coating. So laser-claded nano-Al₂O₃ ceramic coating has higher hardness and better wear resistance than plasma sprayed Al₂O₃+13%TiO₂ coating does.更多还原