镁橄榄石和炭黑为原料合成MgO-SiC-C系复合粉体

Synthesizing MgO-SiC-C Refractory Composite Powder from Forsterite and Carbon Black

以湖北宜昌镁橄榄石细粉与炭黑为原料,分别以4种质量比混合均匀,以热固性酚醛树脂作为结合剂,在200 MPa压力下压制成20 mm×20 mm试样,置于110℃干燥箱中干燥24 h,然后在高温管式气氛炉中通入氩气作为保护气氛,分别在1 550℃1、600℃1、650℃和1 700℃保温3 h烧成.对烧成的试样分别进行X射线衍射和扫描电镜检测,结果表明:原料中Fe2O3杂质经高温烧成后转变为FeSi;不同试样经不同温度烧成后都含有少量的MgAl2O4和SiO2;烧成温度与炭黑含量是影响MgO-SiC-C复合粉体合成的重要控制因素,当烧成温度为1 600℃,镁橄榄石细粉与炭黑原料的质量分数分别为79.5%、20.5%和74.5%、25.5%时,能够比较好地合成MgO-SiC-C系复合粉体.

The MgO-SiC-C composite powders are prepared using forsterite（Yichang,Hubei province） and carbon black powders as raw materials.Forsterite and carbon black are uniformly mixed in 4 mass ratios with phenolic resin as the binder,and then cold pressed into the specimens with the size of φ20 mm×20 mm.The samples are dried at 110 ℃ for 24 hours,and sintered at 1 550 ℃,1 600 ℃,1 650 ℃ and 1 700 ℃,respectively,by holding 3 hours in argon atmosphere.Test results for the sintered samples using XRD and SEM show that after high temperature sintering,Fe2O3 is transformed into FeSi,a few MgAl2O4 and SiO2 phases exist in samples,and that the sintering temperature and the carbon black content are the key factors to affect synthesizing of MgO-SiC-C composite powders.The MgO-SiC-C composite powders are synthesized well when the mass fractions of forsterite and carbon black are 79.5% and 20.5% or 74.5% and 25.5% at 1 600 ℃ or 1 650 ℃.