Effect of Preparation Technology on Thermal Stability of Cu Coated MoSi₂ Composite Particles

Cu coated MoSi2 composite particles were prepared by heterogeneous nucleation method.X-ray diffraction (XRD) was used to determine the phases of the Cu coated MoSi2 composite particles.Differential scanning catorometer(DSC) was used to characterize the thermophysical and thermochemical behaviors of the particles.The results indicate that no chemical reaction occurred between Cu and MoSi2 in the range from room temperature to 1 000 ℃.There was Cu2Cl(OH)3 in the particles prepared in the HCl acid solution,and it decomposed to CuO and CuCl with vapor releasing at about 250 ℃.CuCl melted at about 420 ℃.CuO decomposed to Cu2O and O2 at about 800 ℃.The stability of the particals improved when they were prepared in the aqueous solution using alkylphenol ethoxylates as the modificatec,only decomposition reaction of CuO occurred in the range of room temperature to 1 000 ℃.The finer the particles of MoSi2 were ,the higher the nucleation rate was.And the finer the Cu grains were,and the higher the decomposition temperature of CuO formed from oxidation was.