Effect of Shot Particle on the Mechanism of Creating a Modified Layer by Atmospheric Controlled IH-FPP Treatment

Abstract

Basic mechanisms of generating a surface modified layer formed by a previously developed atmospheric controlled IH FPP system, consisting of induction heating system and fine particle peening system, were investigated. Three types of specimen treated at 900°C in argon with Cr, Al 2 O 3 and Cu shot particles were prepared. Surface microstructures of the treated commercial grade pure iron were characterized with a scanning electron microscope (SEM), an energy dispersive X ray spectrometer (EDX) and an X ray diffraction analysis (XRD). When treatment was carried out using Cr particles, the transferred layer and the diffused layer of the shot particle element formed at the treated surface. This was because the radius of Cr atom was almost the same as that of the Fe, thus forming a solid solution in the substrate. Conversely, when the treatment was applied using chemically stable Al 2 O 3 particles, a transferred layer only was observed. In the case of Cu particles, adhesion occurred due to the low melting temperature of Cu particles, resulting in the formation of a thick adhesive layer such as that generated by thermal spraying. These results suggest that the characteristics of the modified layer, generated by the atmospheric controlled IH FPP treatment system, can be controlled by varying the shot particles and other processing parameters. (Received January 11, 2011; Accepted April 4, 2011) Keywords: surface modification, fine particle peening, induction heating, atmospheric control, induction heating fine particle peening (IH FPP) system

Formation of a TiAl₃ Layer by an AIH-FPP Treatment Using Mechanically Milled Particles and Its Wear Resistance

“…Ti-Al 金属間化合物は，軽量で耐食性や耐摩耗性に加えて 耐熱性にも優れるため，高温構造材料としての利用が期待さ れている．実際，自動車のターボチャージャーなどの素材と して最近利用され始めている．しかし，靱性や延性に乏しく 脆いという欠点を有しているため，バルク材を部品形状に機 械加工して利用することは困難である．そこでこの金属間化 合物を，靱性の高い基材へコーティングすることで，その優 れた特性を最大限に活かす試み 1,2) が検討されている． 本研究では，この金属間化合物を鋼の表面に被覆する手法 として，著者らが開発した AIH-FPP (Atmospheric controlled Induction Heating Fine Particle Peening) 処理 [3][4][5][6][7][8][9][10][11][12][13][14] に着目した．…”

Effect of Cr Diffused Layer Formed by AIH-FPP Treatment on Adhesion of DLC Films to a Carbon Steel Substrate

“…It was previously reported that the shot particle elements transferred onto the surface to be processed are diffused into the substrate during heating. 3) For example, when AIH-FPP treatment using Cr particles is applied to steels, a Cr diffused layer is formed on the surface, which is associated with improved corrosion resistance of the steels. 46) It was also reported that when nitriding is applied to steels with a Cr diffused layer, the nitrided layer formed had higher hardness.…”

Surface Modification of Carbon Steel by Atmospheric-Controlled IH-FPP Treatment Using Mixed Chromium and High-Speed Steel Particles

“…In addition, we conducted a study on the improvement effect and a series of experiments attempting to elucidate the mechanism underlining the effect of atmospheric-controlled induction heating and ne particle peening (AIH-FPP) [18][19][20][21][22][23][24][25] . For example, it was previously reported that by performing AIH-FPP on carbon steel using Cr particles, the components of the Cr particles were transferred onto the surface to be processed and diffused inside the substrate to form a Cr diffusion layer, whereby the corrosion resistance of the carbon steel was improved 22) .…”

“…Therefore, a small amount of oxygen is not evacuated but remains in the chamber. This trace oxygen may form oxides on the surface to be processed, which are likely to inhibit the transfer and diffusion of Cr [20][21][22][23] . In the present study, we rst develop a system that reduces the oxygen concentration in the chamber to the order of ppm, much less than a conventional processing apparatus.…”