Procedure for the application of protective coatings of inorganic oxides on metal surfaces. (Machine-translation by Google Translate, not legally binding)

摘要

An enamel coating is electrophoretically applied to steel or nickel-plated steel from a suspension comprising 20 to 70% by weight of an enamel frit and 80 to 30% by weight of water, the suspension having a specific conductivity of from 7000 to 20,000 Á ohms-1 cm.-1. The suspension may contain organic liquids such as isopropanol, ethylene glycol, dioxan, triethanolamine, cyclohexylamine, cyclohexanone or 2,4,6-trimethyl- 1 3,5-trioxane. The suspension may include sodium aluminate, conductivity increasing electrolytes such as alkali metal or ammonium phosphate, and binders such as cellulose or water glass. Prior to the electrophoretic deposition, steel plates may be degreased, heated in H 2 SO 4 and Ni electroplated. During the electrophoretic deposition, the article to be coated may be connected as anode and moved at a uniform speed past cathodes. The deposited layer may be sintered or fused. Electrophoretically applied enamel may be coated with further enamel. Specified enamel frits suitable for electrophoretic application fall within the following ranges:- SiO 2 27-33 35-44 45-65 Al 2 O 3 12-25 0-4.5 0-5 B 2 O 3 15-23 14-20 0-18 Na 2 O 8-12 7-11 10-18 K 2 O 2-6 0-5 F 5À5-9 0-5 1-5 CaO 8-12 - 0-4 TiO 2 - 8-22 0-9 CoO - - 0-2 NiO - - 0-1.5 Fe 2 O 3 - - 0-2 MgO - 0-2 - P 2 O 5 , - 0-4 - Li 2 O - 0-1 - ZrO 2 6-10 - -