Preparation and properties of ZrB ₂ -MoSi ₂ -glass composite powders for plasma sprayed high temperature oxidation resistance coating on C/SiC composites

An efficient preparation method has been proposed to obtain ZrB ₂ -MoSi ₂ -borosilicate glass (ZMG) powder with good sphericity and appropriate particle size, in order to meet the requirements of atmospheric plasma spraying (APS) process. Agglomerated ZMG powder was prepared by spray drying granulation, and then densified by calcination process and induction plasma spheroidization (IPS) process respectively. The influence of the preparation process on the agglomerated particles, and the spraying adaptability of spray powders densified by two different methods were studied. The optimized parameters of spray drying granulation process were as follows: solid content of slurry was 40%, binder content was 0.3% and inlet temperature was 250 °C, atomizing disk rotating frequency was 50 Hz, feed speed was 100 ml/min. The flowability of ZMG particals was increased by 57.6%, and the apparent density was increased by 96.7% after IPS process. The ZMG coating sprayed by IPS powder is compact and tightly combined with the C/SiC substrate, which indicates the excellent spraying properties of the prepared IPS powder.