热喷涂制备MoSi2高温结构材料的工艺研究

Hot Spraying Technique for MoSi2-based High-temperature Structural Materials

通过大气等离子喷涂制备了MoSi2结构材料,研究了热等静压对MoSi2构件微观结构及性能的影响。结果表明:喷涂成形件主要由MoSi2、Mo5Si3、Mo3Si和Mo组成,呈典型的层状结构特征,内部孔隙和裂纹较多。粉末部分氧化造成硅元素挥发,导致材料出现贫硅现象,使成形件内部存在富钼相。热等静压处理后,MoSi2构件内部孔隙、缝隙减小,致密化效果明显。经1 600℃处理后,MoSi2构件的密度达到6.29 g/cm3,较处理前提高了5.0%;同时其显微硬度也有一定升高。

MoSi2-based structure materials have been fabricated through atmospheric plasma spraying process. The influences of hot isostatic pressing on the microstructures and mechanical properties of MoSi2 products have been studied. The results showed that the spraying-formed products mainly consist of MoSi2, M05Si3, M03Si, Mo and take typical layered structures with certain amounts of fine pores and micro-cracks. Partial oxidation of the powder led to volatilization of Si element, making silicon deplete and Mo-rich phase form in the products. After hot isostatic pressing, the porosity in MoSi2 products decreased, indicating an obvious densification effect. A density of 6.29 g/cm^3 has been achieved after hot isostatic pressing at 1 600 ~C, 8% higher than that before hot isostatic pressing. Meanwhile, there was a certain increase in the microhardness.