前处理工艺对镁合金钛/锆转化膜耐蚀性能的影响

Effect of pre-treatment processes including acid pickling and acid pickling plus alkaline cleaning on the corrosion resistance of achromium-free zirconate-titanate based conversion coating on AZ91D magnesium alloy was systematically investigated. The results indicated that the acid pickling could induce the preferential dissolution of phase and thereby increase the surface roughness of AZ91D magnesium alloy, but which was not conductive to the enhancement of the corrosion resistance of the conversion coating. However, the acid pickling plus alkaline cleaning could appropriately modulate the surface chemical state of AZ91D magnesium alloy, and therefore effectively improve the corrosion resistance of the zirconate-titanate based conversion coating.