Patents Examined by Steven P. Marqus
  • Patent number: 4915799
    Abstract: In this electrolytic coloring method for chromium alloy, first, an aqueous solution containing, for example, chromic acid of 250 g/l as a main material and, for example, sulfuric acid of 490 g/l as an electrolyte is prepared. Then, in this aqueous solution, chromium alloy, for example, a stainless steel plate undergoes an anode electrolytic treatment and a cathod electrolytic treatment respectively for one or more seconds with a current having an average current density of 0.05-2 A/dm.sup.2 respectively one or more in an alternatingly repeated manner, and thereby an oxide film is formed on the surface of the chromium alloy. In this case, the color tone of the oxide film formed on the chromium alloy is adjusted by varying the respective average current densities, the respective treating times and the numbers of repetition cycles of the anode electrolytic treatment and the cathode electrolytic treatment.
    Type: Grant
    Filed: February 19, 1987
    Date of Patent: April 10, 1990
    Assignee: Kinki Yakuhin Industrial Co., Ltd.
    Inventors: Hideki Iai, Katsuaki Shimouchi, Yoshikazu Aoki