原位合成MoSi_(2)-SiC复合粉末

In-situ Synthesis of MoSi_(2)-SiC Composite Powder

为了改善二硅化钼(MoSi_(2))的低温抗氧化性,本文提出了一种原位合成MoSi_(2)-SiC复合粉末的工艺。首次使用MoS_(2)、Si和C作为原料制备MoSi_(2)-SiC复合粉末,相较于Mo、Si和C作为原料可极大降低原料成本。结果表明:当原料中MoS_(2)∶Si∶C的摩尔比为1∶(4+x)∶x时,在1400℃反应2 h即可制备MoSi_(2)-SiC复合粉末,并且可以通过调控x值来调整产物中SiC的比例。制备的SiC颗粒均匀分布在MoSi_(2)晶粒表面和晶界上,并且随着温度的增加,SiC与MoSi_(2)一同长大。当温度为1500℃时,随着产物中SiC比例的增加,MoSi_(2)的晶粒逐渐减小,这是由于部分生成的SiC分布在MoSi_(2)晶界处抑制了其长大。

In order to improve the low-temperature oxidation resistance of molybdenum disilicide(MoSi_(2)),an in-situ synthesis strategy for the synthesizing of MoSi_(2)-SiC composite powder was proposed.In this strategy,using MoS_(2),Si and C as raw materials for the first time can greatly reduce the cost of raw materials compared to using Mo,Si and C as raw materials.The results have shown that when the sample with the MoS_(2):Si:C molar ratio of 1:(4+x):x and reacted at 1400℃for 2 hours,MoSi_(2)-SiC composite powder can be prepared.In addition,the proportion of SiC in the MoSi_(2)-SiC composite powder can be adjusted by adjusting the value of x.The prepared SiC particles are uniformly distributed on the surface and the boundaries of MoSi_(2) grains,and as the temperature increases,SiC and MoSi_(2) grains both grow.Moreover,at 1500℃,as the proportion of SiC in the product increases,the crystal grains of MoSi_(2) gradually decrease.This is because part of the generated SiC is distributed at the grain boundaries of MoSi_(2),inhibiting its growth.