反应火焰喷涂工艺对复相陶瓷涂层孔隙率和硬度的影响

Influence of reactive flame spraying process on properties of multi-phased ceramic coating

以Ti粉、B4C粉和蔗糖(碳的前驱体)为原料,采用反应火焰喷涂技术在钢基体表面制备了TiC-TiB2复相陶瓷涂层,研究了反应火焰喷涂工艺参数(喷涂距离、送粉气压力和喷涂团聚粉的预热温度)对涂层孔隙率和显微硬度的影响。结果表明,在一定条件下,随喷涂距离增加、送粉气压力增大、喷涂粉体预热温度升高,涂层的孔隙率和显微硬度均分别表现出减少和增加的趋势。正交试验结果表明,Ti-B4C-蔗糖体系制备TiC-TiB2涂层最佳工艺条件是喷涂距离为220 mm,送粉气压力为0.3 MPa,团聚粉预热温度为240℃。涂层主要由TiC0.3N0.7、TiB2与TiO2相及孔隙组成,其中TiC0.3N0.7-TiB2为涂层的主相,TiO2为副产物相。涂层与基体之间既有机械结合,又有冶金结合。

With Ti, B4C and sucrose （precursor of carbon） as raw materials, the TiC-TiB2 multi-phased ceramic coatings were prepared on the surface of steel substrate by reactive flame spraying technology. The influences of process parameters （such as spray distance, powders delivering gas pressure and preheating temperature to spray particles） on the porosity and micro-hardness of the coatings were studied. The results show that, under certain conditions, with increasing the spray distance, powders delivering gas pressure and heating temperature to spray particles, the porosity of the coatings has the trend to decrease and the micro-hardness of the coatings has the trend to increase. The orthogonal tests results show that,the process condition of the reactive flame spraying TiC-TiB2 ceramic coatings with Ti-B4C-sucrose system as spray particles is ： spray distance of 220mm, powders delivering gas pressure of 0.3 MPa and heating temperature to spray particles of 240℃. The coatings are mainly composed of TIC0.3 N0.7 phase, TiB2 phase and TiO2 phase, as well as some pores. There are both mechanical bonding and metallurgical bonding between the coatings and the substrate.