Water atomized catalyst powder of Fe70Ni30 is commonly used in synthesizing diamond in recent years in China. The powder features including morphology, composition, particle size distribution, oxygen content and phase composition were analyzed. The results indicated that the powder showed irregular shape; the particle size was in a normal distribution, D50 = 22. 9 μm; the impurity content was very low; the initial oxygen content was 0. 2% (mass fraction). 30% (mass fraction ) catalyst powder and 70% (mass fraction) graphite powder were mixed and suppressed into a synthesizing rod. After sintered at temperature of 1 000 t in vacuum of 10 ~2 Pa for 6 hours ,the oxygen content of catalyst was reduced to 0.011 7%( mass fraction) , this reached the level of gas atomized powder Fe70Ni30 and was good for synthesizing diamond. There was more gamma phase and little alpha phase in the original powder, and the alpha phase increased after high temperature sintering in vacuum., which during diamond synthesis of high temperature and high pressure, would be changed into gamma phase. Single gamma phased alloy is very helpful in the diamond nucleation and grow up.%我国近年普遍采用水雾化粉末触媒Fe70 Ni30合成金刚石,本文对这种粉末形貌、成分、粒度分布、氧含量、相组成等作了分析研究.结果表明:粉末呈不规则状；粒度呈正态分布,D50= 22.9 μm；粉末杂质含量很低:初始粉氧含量为0.2％(质量分数),将触媒粉和石墨粉混合(质量比3:7)压成合成柱,在1000℃,真空10-2 Pa,6h脱氧处理后,可使触媒粉的氧含量降到0.011 7％(质量分数),达到气雾化粉末的水平,对合成金刚石是非常有利的.Fe70Ni30初始粉由大量的γ相和少量α相组成,合成柱经高温真空处理后,α相含量较处理前含量增多,高温高压合成中会变成单一的γ相,单一的γ相合金十分有利于金刚石的成核与长大.
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