缓蚀剂对水基环保免清洗助焊剂缓蚀性能的影响

Effect of corrosion inhibitor on corrosion inhibition performance of water-based environmental-friendly no-clean flux

以丁二酸、苹果酸(w=2.00%)为活化剂,乙二醇、异丙醇和乙二醇丁醚(w=3.00%)为助溶剂,聚乙二醇-6000(w=0.25%)为成膜剂,咪唑(IM)、苯并咪唑(BIA)和苯并三氮唑(BTA)分别为缓蚀剂,配制系列水基免清洗助焊剂。用静态失重法、电化学阻抗谱法和扫描电子显微镜等方法研究了三种缓蚀剂对金属铜的缓蚀作用。结果表明:随三种缓蚀剂含量的增加,缓蚀率均表现出先提高后降低的趋势。其中BTA的添加量为0.08%时,缓蚀率达88.78%,金属膜电阻Rf达1.25×106·cm2,缓蚀效果最佳。研究还表明:缓蚀剂总量为0.08%时,BIA和BTA复配(0.04%BIA+0.04%BTA),缓蚀率达94.25%,Rf达2.26×106·cm2,显示出明显的缓蚀协同效应。助焊剂铺展实验也表明,复配缓蚀剂的最佳添加量为0.04%BIA和0.04%BTA。

A series of water based environmental-friendly fluxes were prepared with succinic acid and malic acid compounded （w=2.00%） as activator, glycol, isopropanol and ethylene glycol butyl ether compounded （w=3.00%） as co-solvent, polyethylene glycol 6000（w=0.25%） as film-forming reagent, and imidazole （IM）, benzimidazole （BIA）, benzotriazole （BTA） as corrosion inhibitor respectively. The corrosion inhibition performance of imidazole, benzimidazole, benzotriazole on the copper in the flux was investigated with the static weight-loss method, electrochemical impedance spectroscopy （EIS） and scanning electron microscope （SEM）. Corrosion inhibition efficiency increased firstly with the increase of concentration of inhibitor, but decreased over the optimum concentration. With 0.08% benzotriazole as inhibitor, the inhibiting rate was up to 88.78%, metal film resistance Rf was up to1.25× 106 Ω. cm2 , and the flux showed better corrosion inhibition. The research also indicated that inhibiting rate was up to 94.25% and Rf was up to 2.26× 106 Ω· cm2, when the content of the compounded inhibitor remained as 0.08% and the mass ratio of BIA and BTA was 1：1 in the flux. These results indicated that there was a good synergistic effect after BIA and BTA compounded as inhibitor. A tight absorbed protective film was formed after the addition of compounded corrosion inhibitors together, which might be the main reason that inhibited and reduced copper corrosion. The data of spreading area of flux also indicated that the suitable amountof compounded corrosion inhibitors was 0.04% BIA and 0.04% BTA.