Simultaneous plasma treatment for carburizing and carbonitriding using hollow cathode discharge
- Ibaraki Univ., Hitachi, Ibaraki (Japan). Dept. of Materials Science
Ion carburizing and nitriding are effective processes for saving energy and providing pollutionless surface treatment but have the disadvantage of using much electric energy. A cylindric subsidiary cathode was set up around a rod-shaped workpiece with a gap, and hollow cathode discharge for ion carburizing was studied. Thus, simultaneous plasma treatments for ion carburizing and ion carbonitriding in one workpiece were researched using Cr-Mo steel to save electric treatment power. First, the effects of the gap between the test piece and subsidiary cathode and the pressure of electric discharge gas, including methane gas, on fundamental plasma treatment conditions were experimentally researched. It was found that the temperature for ion carburizing in a H{sub 2}-N{sub 2}-Ar-CH{sub 4} gas mixture was 1,123 to 1,193 K with a gap of 3 to 5 mm under a gas pressure of 133 to 532 Pa. Next, the test piece was ion carburized with hollow cathode discharge and carbonitrided with normal glow discharge simultaneously. The ion-carburized layer was formed in the area covered by the subsidiary cathode. The surface hardness was 800 Hv, the effective case depth was 0.6 mm, and the surface carbon content was 0.75 wt pct. An ion carbonitriding layer was formed in the area without the subsidiary cathode. The surface hardness was 700 Hv and the case depth was 0.1 mm. It is useful to form the different layers of ion carburizing and ion carbonitriding in one treatment process and to give different mechanical and tribological properties on one workpiece simultaneously.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 207690
- Journal Information:
- Metallurgical Transactions, A, Vol. 27, Issue 2; Other Information: PBD: Feb 1996
- Country of Publication:
- United States
- Language:
- English
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