(中南大学 粉末冶金国家重点实验室，长沙 410083)
摘 要: 采用紧耦合气雾化法制备SnAgCu无铅焊料合金粉末，研究雾化压力和熔体过热度对粉末粒径和形貌的影响。采用干筛筛分法对所制备的粉末进行分级，采用激光粒度分析仪和扫描电镜分别对粉末的粒径、形貌和微观组织进行表征。结果表明：当雾化压力为0.7 MPa、熔体过热度为20~30 ℃时，制备的无铅焊料合金粉末中值粒径为40.10 µm，颗粒表面光洁、球形度高；当过热度为20~30 ℃、雾化压力由0.7 MPa增大至2.5~3.0 MPa时，粉末中值粒径由40.10 µm减小至32.22 µm，颗粒表面缺陷明显增多；当雾化压力为0.7 MPa、熔体过热度由30 ℃提高至50 ℃时，粉末粒径仅略微减小，但球形度明显降低；气雾化快速冷凝产生富Ag和Cu相，且富Ag和Cu相弥散分布在Sn基体内。
关键字: SnAgCu；合金粉末；无铅；气雾化
SnAgCu alloyed powder prepared by gas atomization
（State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China）
Abstract:SnAgCu lead-free solder powders were prepared by close-coupled gas atomization. The effects of gas atomization pressure and melt superheat on the powder size and morphologies were investigated. Dry sieving was used to classify the alloyed powder. Laser light diffractometry and scanning electricity microscopy were used to characterize the size and morphologies of the powder. The results indicate that when the gas atomization pressure is 0.7 MPa and the melt superheat is 20−30 ℃, the alloyed powder with mass medium diameter of 40.10 µm is obtained, which is satellite-free and high sphericity. When the superheat is 20−30 ℃, with the gas atomization pressure increasing from 0.7 MPa to 2.5−3.0 MPa, the powder size decreases from 40.10 µm to 32.22 µm whereas the surface defective of the powder increases obviously. When the gas atomization pressure is 0.7 MPa, with the melt superheat increasing from 30 ℃ to 50 ℃, the powder size decreases a little but the sphericity of the powder becomes worse. Rich Ag and Cu phase forms during quick cooling of gas atomization, disperses well in the Sn-matrix.
Key words: SnAgCu; alloyed powder; lead-free; gas atomization
