Improvements in or relating to the formation of phosphate-chemical conversion coatings upon metal surfaces
Реферат: In phosphating iron and steel, the metal surface is contacted with an aqueous acidic solution of an alkali metal phosphate (the term including mono and dihydrogen phosphates of ammonia and the alkali metals) together with nitrite ions and at least 0.05 g./1. of a hydrazine compound of the general formula: <FORM:0970197/C6-C7/1> (wherein A represents hydrogen, an unsubstituted alkyl radical having from 1 to 3 carbon atoms or the phenyl radical and B represents hydrogen, the methylcarbonyl radical or the carbamyl radical). The pH of the solution is from 4.0 to 5.8 (e.g. 4.5 to 5.7) and the temperature at least 120 DEG F. (49 DEG C. approx.) (e.g. 120-150 DEG F.). The nitrite ion concentration is related to the hydrazine compound concentration by a specified formula. Specified hydrazine compounds are hydrazine, methyl-, ethyl-, propyl-, phenyl-, b aceto a phenyl-, b aceto a methyl hydrazines and semicarbazide. The nitrite may be the alkali or alkaline earth metal salt, e.g. NaNO2. The solution may include a wetting agent and may be applied by dipping, spraying or roller coating In Example I, steel panels are enamelled after phosphating.
Process for the phosphate chemical conversion treatment of a steel material
Номер патента: US4880476A. Автор: Kazuhiko Mori,Shigeki Matsuda,Wataru Gotou,Takahiro Ohnuki. Владелец: Nihon Parkerizing Co Ltd. Дата публикации: 1989-11-14.