(中南大學(xué) 粉末冶金國家重點實驗室，長沙 410083)
摘 要: 采用緊耦合氣霧化法制備SnAgCu無鉛焊料合金粉末，研究霧化壓力和熔體過熱度對粉末粒徑和形貌的影響。采用干篩篩分法對所制備的粉末進行分級，采用激光粒度分析儀和掃描電鏡分別對粉末的粒徑、形貌和微觀組織進行表征。結(jié)果表明：當(dāng)霧化壓力為0.7 MPa、熔體過熱度為20~30 ℃時，制備的無鉛焊料合金粉末中值粒徑為40.10 µm，顆粒表面光潔、球形度高；當(dāng)過熱度為20~30 ℃、霧化壓力由0.7 MPa增大至2.5~3.0 MPa時，粉末中值粒徑由40.10 µm減小至32.22 µm，顆粒表面缺陷明顯增多；當(dāng)霧化壓力為0.7 MPa、熔體過熱度由30 ℃提高至50 ℃時，粉末粒徑僅略微減小，但球形度明顯降低；氣霧化快速冷凝產(chǎn)生富Ag和Cu相，且富Ag和Cu相彌散分布在Sn基體內(nèi)。
關(guān)鍵字: SnAgCu；合金粉末；無鉛；氣霧化
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
