Symposium G Poster Session

Thursday, May 1, 2014 5:00 PM in Room Town & Country and San Diego

GP-1 Fabrication and Characteristics of Ceramic/Ni-Cr-Mo Steel Coatings by Centrifugal Casting Process
H. Kim (Sejong University, Korea); K. Oh, N. Yi, S. Kim (S.M. Metal, Korea); K. Park (Sejong University, Korea)

In this study, ceramic/Ni-Cr-Mo steel coatings were fabricated by centrifugal casting process. The microstructure and characteristics of the ceramic/Ni-Cr-Mo steel coatings prepared by the centrifugal casting process were discussed, depending on the rotation velocity of mold and the pouring temperature of Ni-Cr-Mo steel. The specimen with a size of 10×10×10mm3 was sectioned, mounted, ground, and polished with a diamond paste for characterization by X-ray diffraction and scanning electron microscopy. We investigated the microstructure of ceramic/Ni-Cr-Mo steel coatings, reaction products between the ceramic and Ni-Cr-Mo steel in the coatings, and microstructural stability of the coatings at high temperatures. The Ni-Cr-Mo steel matrix provided a good toughness supporting ceramics. Liquid infiltration using centrifugal force was highly effective to fabricate ceramic/Ni-Cr-Mo steel coatings. The centrifugal force was sufficient to obtain a full infiltration. Based on the present study, we believe that ceramic/Ni-Cr-Mo steel coatings can be applied in a wide range of industries, such as non-ferrous metal production (e.g., Mg), waste incinerators, boilers, gasification, etc.

GP-3 Desk-top RF-DC Plasma Nitriding System for Automotive Steel Parts
Yoshio Sugita (YS-Eletric Industry, Co. Ltd., Japan); Tatsuhiko Aizawa (Shibaura Intitute of Technology, Japan); Keisuke Tsukui, Eiji Nakayama (Yamanashi University, Japan)
Most of commercial plasma nitriding system was driven by DC- and DC-pulse plasmas. In case of automotive parts such as piston rings or valves, thousands of parts were once installed into a chamber and then subjected to plasma treatment. Being constrained to this nitriding process in batch, a plasma nitriding has less means to be flexible to changing demand for surface treatment. In the present paper, a desk-top plasma nitriding system is proposed as a unit for distributed surface treatment.

The chamber has a diameter of 180 mm and a height of 180 mm. It is composed of a dipole electrode for RF-plasma generation, an IH-device for thermal control and a sample holder with DC-bias. In the present treatment, a product is set-up in this chamber, heated to the specified temperature by IH- device , and, then subjected to plasma nitriding. First, SKD61 is employed as a common work material to investigate the nitriding behavior via SEM observation, XRD and micro-hardness testing and to optimize the nitriding conditions. Next, an engine valve is selected as a typical automotive part for this desk-top plasma nitriding. Homogeneous nitriding takes place under optimum alignment of RF-electrode and IH- device in this system.