Process for manufacturing a piston ring

• US 5,618,590 A
• Filed: 06/05/1995
• Issued: 04/08/1997
• Est. Priority Date: 09/20/1991
• Status: Expired due to Term

• Current Assignee: Teikoku Piston Ring Company Limited (TPR Co., Ltd.)
• Original Assignee: Teikoku Piston Ring Company Limited (TPR Co., Ltd.)
• Inventors: Naruse, Yoshio, Miyazaki, Satomichi
• Primary Examiner(s): Beck, Shrive
• Assistant Examiner(s): CAMERON, ERMA C
• Application Number:
  US08/464,306
• Time in Patent Office: 673 Days
• Field of Search: 427/528, 427/530, 427/531, 427/580, 204/192, 204/12, 204/192.15, 204/192.16
• US Class Current: 427/528
• CPC Class Codes: C23C 14/0688 Cermets, e.g. mixtures of metal and one or more of carbides, nitrides, oxides or borides
• CPC Class Codes: C23C 14/325 Electric arc evaporation
• CPC Class Codes: F16J 9/26 characterised by the use of particular materials

Abstract

Using an arc ion plating apparatus, a metal not capable of forming a carbide or nitride, such as cobalt, nickel or molybdenum is set as a first target, a metal capable of forming a carbide or nitride, such as silicon, titanium, vanadium, chromium, iron, zirconium, niobium or tungsten is set as a second target and nitrogen, acetylene or methane is fed as a process gas to form a film on a piston ring body which is an article to be coated, thereby providing a piston ring comprising a hard film formed on at least its sliding outer face of the piston ring body, said hard film comprising a mixed structure formed of the metal not capable of forming a carbide or nitride and a carbide or nitride of the metal capable of forming a carbide or nitride. In this piston ring, the hard film has so good adhesion to the body material or film toughness that no cracking or film separation tend to occur even when the film is formed in a large thickness. The carbide or nitride in the hard film contributes the achievement of a superior wear resistance. Because of the fine structure of the hard film, the wear of the opposing material can be decreased, no film lubrication tends to be lost and the seizure resistance can be improved.

Claims

1. A process for manufacturing a piston ring, comprising:

(a) causing an arc discharge in a process gas atmosphere comprised of nitrogen or carbon as a component element, using as a cathode a target comprised of (i) a metal selected from the group consisting of cobalt and nickel and (ii) a metal selected from the group consisting of silicon, titanium, vanadium, chromium, iron, zirconium, niobium and tungsten, wherein the cobalt or nickel is applied to the piston ring without forming a carbide or nitride and wherein the metal selected from the group consisting of silicon, titanium, vanadium, chromium, iron, zirconium, niobium and tungsten is applied to the piston ring as a nitride or a carbide, to release metal ions from said target; and

(b) applying a bias voltage to a piston ring body to bring said metal ions together with particles of the process gas, into adhesion to a surface of the piston ring body to form a film coating thereon.

2. The process according to claim 1, wherein said process gas is selected from the group consisting of nitrogen, acetylene and methane.

3. The process according to claim 1, wherein, after said film has been formed, nitriding is carried out.

4. The process according to claim 2, wherein said bias voltage is 50 volts.

5. The process according to claim 2, wherein the film has a thickness of 15 to 70 μ

m.

6. The process according to claim 5, wherein the piston ring body is made of cast iron.

7. The process according to claim 5, wherein the piston ring body is made of steel.

8. The process according to claim 2, wherein the arc discharge is carried out in a vacuum of 1.3×

10^-3 Torr or less.