Noboru Egami

Effect of Fine Particle Bombarding Treatment Conditions on Surface Origination of Materials

In this study, we analyzed effect of fine particle bombarding (FPB) treatment conditions on structural transformation close to the material surface and also measured temperature close to the material surface in FPB treatment. As a result, when an intensive condition was used in FPB treatment, a lamellar structure was observed. In other words, dents and bumps are formed in the initial stage of particle collisions on the material surface. Repeatedly processed, the protruded portions are supposed to be then bent over, resulting in an atomized structure. On the other hand, we measured temperature close to the material surface to find temperature rising up to about 600. In addition, when the fine particle collided continuously to the same portion, the specimen reached a melting state. These results indicate that heat generated in FPB treatment has a drastic effect on structural transformation close to the material surface.

Nondestructive evaluation of residual stress in short-fiber reinforced plastics by x-ray diffraction

The X-ray diffraction method is used to measure the residual stress in injection-molded plates of short-fiber reinforced plastics (SFRP) made of crystalline thermoplastics, polyphenylene sulphide (PPS), reinforced by carbon fibers with 30 mass%. Based on the orientation of carbon fibers, injection molded plates can be modeled as three-layered lamella where the core layer is sandwiched by skin layers. The stress in the matrix in the skin layer was measured using Cr-Kα radiation with the sin2Ψ method. Since the X-ray penetration depth is shallow, the state of stresses measured by X-rays in FRP can be assumed to be plane stress. The X-ray measurement of stress in carbon fibers was not possible because of high texture. A new method was proposed to evaluate the macrostress in SFRP from the measurement of the matrix stress. According to micromechanics analysis of SFRP, the matrix stresses in the fiber direction, σ1m, and perpendicular to the fiber direction, σ2m, and shear stress τ12m can be expressed as the functions of the applied (macro-) stresses, σ1A, σ2A , τ12A as follows: σ1m = α11σ1A +α12σ2A, σ2m = α21σ1A + α22σ2A, τ12m = α66τ12A, where α11 ,α12, α21, α22, α66 are stress-partitioning coefficients. Using skin-layer strips cut parallel, perpendicular and 45° to the molding direction, the stress in the matrix was measured under the uniaxial applied stress and the stress-partitioning coefficients of the above equations were determined. Once these relations are established, the macrostress in SFRP can be determined from the measurements of the matrix stresses by X-rays.

Mask-coating using inorganic agent for chemical vapor deposition treatment.

Mask-Coating Using Inorganic Agent for Chemical Vapor Deposition Treatment by Chuji KAGAYA*, Masanori KATO*, Noboru EGAMI** and Masaru IKENAGA*** Chemical vapor deposition (CVD) method is used to deposit hard wear resistant materials such as titanium carbide and nitride onto a substrate. A suitable masking agent for CVD has not yet been developed at present, however. The purpose of this paper was to investigate the possible utilization of inorganic agents for such mask-coating. Both of the portion pre-coated with an inorganic agent and the un-precoated portion have been examined by means of X-ray diffraction analysis, hardness tests and structure observations. The characteristics of the inorganic mask-coating agent were also investigated by differential thermal analysis and gas chromatography. The experimental results showed that masking was successful with this agent. This coating was thermally as well as chemically stable and can be used as a masking agent for the CVD treatment. キー ・ワー ド:無 機 質 コー テ ィ ン グ剤,CVDマ ス キ ン グ剤,示 差 熱 曲 線,分 解 ガス