Patents Assigned to Teiko Piston Ring Co., Ltd.
  • Composite chromium plating film and sliding member covered thereof
    Patent number: 6013380
    Abstract: A piston ring formed with a nitrided layer over all surfaces and formed with a composite chromium plating film over the nitrided layer in the outer circumferential surface. The composite chromium plating film has a network of cracks formed on the outer surface and interior. Si.sub.3 N.sub.4 particles are fixed in these cracks. The average size of the Si.sub.3 N.sub.4 particles is 0.8 to 3 .mu.m and the dispersion ratio of the Si.sub.3 N.sub.4 particles is 3 to 15 percent by volume.
    Type: Grant
    Filed: November 10, 1997
    Date of Patent: January 11, 2000
    Assignee: Teiko Piston Ring Co., Ltd.
    Inventors: Akira Harayama, Toshiaki Imai