文档介绍：1
2olution first and then deposita Ce (NO3 ) 3 conversion coating. Hydrogen release exam ination, weight
lost test dipp ing in alkali and salt sp ray test p rove that the corrosion resistant p roperty of the compound film
better than single Ce (NO3 ) 3 conversion coating, even better than some chromate conversion coatings. Tafel
polarization curves and AC impedance tests show that the compound film blocks the cathodic reduction reac
tion in Zinc s electrochem ical corrosion and increases the resistance of electric charge transfer, therefore to
reduce corrosion rate of Zinc significantly. XRD, SEM analysis indicates that the main substance in conver
sion coating is CeO2 , which causes the compound film more compact and higher coverage on Zinc substrates.
The mechanism of film - form ing and corrosion p rotection are discussed p relim inarily.
Key W ords: galvanized steel; compound film;γ - APS; ceriam salt; corrosion resistance
人们围绕无铬钝化作了大量研究 ,但迄今为止 ,仍有许多问题
0 引 言 没有解决 ,如耐腐蚀性达不到要求 ,处理时间长 、工艺复杂 ,对