发明授权
US4622078A Process for the zinc/calcium phosphatizing of metal surfaces at low treatment temperatures 失效
在低处理温度下金属表面的锌/钙磷酸化过程

Process for the zinc/calcium phosphatizing of metal surfaces at low
treatment temperatures
摘要:
The invention relates to a process for phosphatizing metal surfaces with an acidic phosphatizing solution containing zinc ions, calcium ions, phosphate ions and accelerators and, optionally, other additives, characterized in that, after degreasing and without activation, the metal surfaces are brought into contact at 30.degree. to 65.degree. C. with solutions which contain Zn.sup.2+, Ca.sup.2+, PO.sub.4.sup.3- and, as accelerators, nitrate and/or nitrite and/or chlorate ions and/or an organic nitro compound and/or H.sub.2 O.sub.2 or an inorganic peroxide and which have a pH-value of from 2.2 to 3.8, a ratio of free acid to toal acid of from 1:10 to 1:60 and a ratio by weight of (Ca.sup.2+ +Zn.sup.2+) to PO.sub.4.sup.3- of from 1:>8 to 1:40, and to the use of this process for pretreating the metal surfaces for painting by electrodeposition, particularly by cathodic electrodeposition.
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