喷雾转换法制备纳米WC-6Co复合粉的工艺研究

Technological Study of WC-6Co Nanocomposite Powder Preparation with Spray Conversion Method

以偏钨酸铵、醋酸钴、有机碳为原料,去离子水为溶剂,采用喷雾干燥-煅烧-球磨-连续还原碳化新工艺制备纳米WC-6Co复合粉。采用氮气吸附法测定粉末比表面积,XRD、SEM分别分析粉末物相和形貌,研究球磨工艺对钨钴复合氧化物粉末性能的影响以及连续还原碳化过程中粉末比表面积的变化。结果表明,在连续还原碳化前进行球磨,可有效破碎粉末;适当增大球料比或延长球磨时间,可使粉末破碎效果更好,粒度分布更均匀,当球料比为10∶1、球磨时间为240min时,粉末破碎、分散效果最佳,比表面积为11.62m2/g;球磨后的钨钴复合氧化物粉末在连续还原碳化过程中发生团聚烧结、预合金化,生成平均粒度为80nm的WC-6Co复合粉。

Using ammonium metatungstate（AMT）,cobalt acetate and organic carbon as raw materials and deionized water as solvent,WC-6Co nanocomposite powder was prepared by the new technology of spray drying-calcination-ball milling-continuous reduction carbonization.Specific surface area,phase composition and morphology of the powder were analyzed by nitrogen adsorption method,X-ray diffraction（XRD）and scanning electron microscope（SEM）,respectively.The effects of ball milling on the performance of W-Co composite oxide powder were investigated as well as specific surface area change of the powder during continuous reduction carbonization.The experimental results show that ball milling before continuous reduction carbonization can effectively crush the powder.And the powder has better crushing effect and more uniform particle size distribution by increasing ball to powder ratio or extending ball milling time.When the ratio and time are 10∶1and 240 min,the powder has the optimal crushing and dispersing effect with 11.62m2/g specific surface area.Ball-milled W-Co composite oxide powder is agglomerated,sintered and pre-alloyed during continuous reduction carbonization to generate WC-6Co composite powder with an average particle size of 80 nm.