Process of electrolytic surface treatment of metals

Claim 1

A PROCESS FOR ELECTROLYTIC SURFACE TREATMENT OF METALS WHEREIN DEGREASING, PICKLING AND POLISHING OF THE METAL SURFACES ARE SIMULTANEOUSLY CARRIED OUT IN A SINGLE ALKALINE BATH, SAID PROCESS COMPRISING IMMERSING A METAL ARTICLE AND AN ELECTRODE IN SAID BATH AND PASSING AN ALTERNATING CURRENT BETWEEN THE ARTICLE AND SAID ELECTRODE, SAID ALTERNATING CURRENT BEING USED AT BETWEEN 5 AND 30 VOLTS AND AT A CURRENT DENSITY OF SUBSTANTIALLY 20-200 AMPERES PER DM.2, SAID BATH CONSISTING ESSENTIALLY OF (A) AN ALKALINE DEGREASING AGENT SELECTED FROM THE GROUP CONSISTING OF CAUSTIC SODA, SODIUM ORTHOSILICATE AND SODIUM METASILICATE, SAID DEGREASING AGENT BEING IN AMOUNTS BETWEEN 20 AND 200 G./L.; (B) AN ALKALINE CYANIDE AS AN ALKALINE PICKLING AGENT, SAID PICKLING AGENT BEING IN AMOUNTS BETWEEN 25 AND 250 G./L.; (C) A TENSIO-ACTIVE AGENT SELECTED FROM THE GROUP CONSISTING OF AN ALKALINE SALT OF A FATTY SECONDARY SULFONATED ALCOHOL, AN ALCOYLARYL-SULFONATE AND SODIUM SULFORICINATE, SAID TENSIO-ACTIVE AGENT BEING IN AMOUNTS BETWEEN 0.5 AND 20 G./L.; AND (D) A CHELATING AGENT SELECTED FROM THE GROUP CONSISTING OF POLYPHOSPHATES, A SODIUM SALT OF ETHYLENE DIAMINOTETRACETIC ACID, TERTIARY AMINO-ALCOHOLS, AND POLYACIDS-ALCOHOLS, SAID CHELATING AGENT BEING IN AMOUNTS BETWEEN 5 AND 100 G./L.