相反转法制备超细Bi-Pb-Sn-Cd易熔合金粉

用相反转法将含分散剂的水滴加到熔融的Bi-Pb-Sn-Cd易熔合金液中,制备了一系列超细合金粉,使超细粉的制备与表面修饰同步进行,系统研究了制备过程中温度、搅拌速度和分散剂浓度对超细合金粉粒径的影响。实验结果表明,随着水在合金液中含量的增加,体系发生相转变,合金从连续相逐渐破裂成分散相而形成超细金属粉,同时改性剂以物理吸附的方式对超细金属粉进行表面改性;制备温度、搅拌速度和分散剂浓度对合金粉粒径有明显影响,以浓度为1%的油酸钠为分散剂,温度为85℃,搅拌速度为1750r.min-1,可制得平均粒径为0.3μm的超细Bi-Pb-Sn-Cd合金粉。为获得满意粒径和表面改性效果的超细合金粉,必须将制备温度、搅拌速度和分散剂浓度控制在适当的范围。

Preparation of superfine Bi-Pb-Sn-Cd fusible alloy by phase inversion

Superfine Bi-Pb-Sn-Cd fusible alloy powders were prepared with the method of phase inversion，in which water drops containing dispersant were added into Bi-Pb-Sn-Cd alloy melt gradually to facilitate surface treatment.The effects of temperature，stirring speed and dispersant content on average particle size of alloy were investigated.The results showed that by adding water，the phase of Bi-Pb-Sn-Cd alloy inversed from continuous phase to dispersed phase，dispersant was adsorbed on the surface of the dispersed phase，and superfine powders with surface treatment were obtained.Temperature，stirring speed and dispersant content strongly affected average size of alloy powder.When dispersant content was 1%，temperature was 85℃ and stirring speed was 1750 r·min^-1，Bi-Pb-Sn-Cd alloy powder with average size of 0.3 μm was prepared.In order to obtain alloy powder of required size and surface treatment，temperature，stirring speed and dispersant content must be kept in a proper range.