Patents by Inventor Gerrit Krijl

Gerrit Krijl has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Method of making an article having a layer of a nickel-phosphorus alloy and coated with a protective layer
    Patent number: 4545871
    Abstract: An article which is covered with a nickel-phosphorus alloy is covered on its outer surface with a protective layer which comprises CrPO.sub.4, Cr(OH).sub.3 and may also comprise Cr.sub.2 (SO.sub.4).sub.3 and in which no nickel is present. The layer provides excellent corrosion protection. In a particular embodiment the layer is black, scratch-resistant in normal use, cannot be wiped off and is not sensitive to finger prints and is extremely suitable for decorative applications. The layers can be obtained electrolytically in a bath which comprises chromic acid and optionally phosphoric acid and sulfuric acid using reversed current in a given frequency range, a given range of current densities and a given range of ratios of cathodic to anodic pulse durations. In order to obtain the black layers the cathodic time duration is only a fraction of the anodic time duration.
    Type: Grant
    Filed: November 2, 1984
    Date of Patent: October 8, 1985
    Assignee: U.S. Philips Corporation
    Inventors: Gerrit Krijl, Renaat E. Van de Leest
  • Metal article layered with a nickel-phosphorus alloy and a protective coating
    Patent number: 4497877
    Abstract: A metal article which covered with a nickel-phosphorus alloy and which is covered on its outer surface with a protective layer which comprises CrPO.sub.4, Cr(OH).sub.3 and may also comprise Cr.sub.2 (SO.sub.4).sub.3 and in which no nickel is present. The layer provides an excellent corrosion protection. In a particular embodiment the layer is black, scratch-resistant in normal use, cannot be wiped off and is not sensitive to finger prints and is extremely suitable for decorative applications. The layers can be obtained electrolytically in a bath which comprises chromic acid and optionally reversed current in a given frequency range, a given range of current densities and a given range of ratios of cathodic to anodic pulse durations. In order to obtain the black layers the cathodic time duration is only a fraction of black layers the anodic time duration.
    Type: Grant
    Filed: May 3, 1983
    Date of Patent: February 5, 1985
    Assignee: U.S. Philips Corporation
    Inventors: Gerrit Krijl, Renaat E. Van de Leest
  • Method of treating objects the surface of which consists of tin
    Patent number: 4273625
    Abstract: Treating objects of which at least the surface consists of tin in order to obtain a satisfactory corrosion resistance. To this end the objects are subjected in a tungstate solution of at least 0.02 M and having a pH of 4-11 alternately to a cathodic and an anodic polarity (so-called periodically reversed current). The frequency with which the current reverses must be between 0.2 and 2 Hz and the current density must be between 0.2 and 1 A/dm.sup.2, the ratio of the anodic to the cathodic density being from 0.5-1.
    Type: Grant
    Filed: August 14, 1980
    Date of Patent: June 16, 1981
    Assignee: U.S. Philips Corporation
    Inventors: Renaat E. Van de Leest, Gerrit Krijl, Ewoud A. Boonzajer Flaes