高压水雾化金刚石铁基触媒粉的工艺研究

采用典型检验和统计分析的方法研究了FeNi30高压水雾化金刚石触媒粉的形貌、氧含量、粒度与粒度组成及合成效果。结果表明,粉末为近球形颗粒,-200目产出率为68.2%。由于原有高压水雾化金刚石触媒粉的氧含量较高,不能直接在合成金刚石中使用。水雾化的触媒粉通过1 000℃,真空10-2Pa,6 h高温真空脱氧处理,触媒粉中氧的质量分数降到200×10-6～500×10-6,满足合成金刚石的要求。Φ38 mm腔体批量合成的单产达50～87 carat,粒度35/60目的金刚石粉达到46.5%至82.5%。粒度为-250目的触媒合成的金刚石品质较好,但与气雾化金刚石触媒粉相比,粒度还较粗,因此还需要不断改进雾化装置和雾化工艺,不断提高触媒粉成品率和品质。

Study on the Process of Diamond Iron-based Catalyst Powder by High-pressure Water Atomization

The technology process of the water atomized catalyst powder was discussed in this paper. The metal materials were melt in the intermediate frequency furnace in the proportion of 70 pure iron to 30 nickel, then atomized by overheating and high-pressure water in the atomized equipment. Because of the high oxygen content, the water atomized catalyst powder can＇t be used directly in the diamond synthesizing. So through the deoxidization at the temperature of 1 000 ℃ in vacuum of 10-2 Pa for 6 h, the oxygen content was reduced to 200×10^-6～500×10^-6, which can meet the requirement of diamond synthesizing. The diamond-synthesizing resuh shows that the experiment on the catalyst powder in a 38 mm cavity is a success, which provides a new method for the preparation of low-cost catalyst powder. The synthetic diamond would achieve high quality if the particle size of the catalyst powder can be controlled to -250 mesh. The -200 mesh yield of the catalyst powder produced by the existing high-pressure water atomized equipment is only 68.2%, still not high. Compared with the air atomized catalyst powder, its particle size is relatively rough. Thus, the atomized equipment needs improvement to enhance the product quality. The physical characteristics, morphologies and particle size composition of the iron-based catalyst powder made by high-pressure water atomization are also introduced in this paper.