Ni2+对铝合金磷化膜结构和耐蚀性的影响

摘要

Effect of Ni2 + on structure and corrosion resistance of zinc system phosphate conversion coating on aluminum alloy LY12 was studied by surface analysis approaches and electro-chemical technologies. Results showed that main component of the coating was Zn3(PO4)2 · 4H2O, structure of the coating became more complete and compact due to grain refinement function of the Ni2+ and both chemical and phase composition of the coating were not affected by the Ni2+ , for the aluminum alloy phosphated in Ni2+ containing bath, corrosion current density decreased clearly and impedance increased clearly at 100 mHz frequency in 3.5% NaCl solution compared with that in Ni +-free phosphating bath.%通过表面分析和电化学测试等研究了Ni2+对LY12铝合金表面锌系磷化膜结构和耐蚀性的作用.结果表明,LY12铝合金表面锌系磷化膜的主要成分是Zn3( PO4)2·4H2O,而Ni2+的细化晶粒作用使锌系磷化膜的结构变得更加完整致密,其加入不影响锌系磷化膜的化学组成和相组成；与不含Ni2+的磷化液处理相比,经含有Ni2+的磷化液处理后的铝合金在3.5％的NaCl溶液中的腐蚀电流密度明显下降,在100 mHz频率下的阻抗值明显增大,表现出良好的防护性.