Abrasive grains used in grinding are classified by their size and crushing strength. In a single-layered electroplated diamond grinding wheel and a grinding wheel on which diamond grains are deposited at the same interval, the properties of the individual abrasive grains influence the processing accuracy. Therefore, it is important to determine their precise characteristics as the shape and distribution affect processing efficiency. However, measurement and analysis methods for this purpose have yet to be established. Therefore, a measurement system was developed to quantitatively evaluate the shape of the facets by image processing. This paper presents results of an experiment for several kinds of abrasive grain.

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Silicon carbide (SiC) is a good candidate material for next-generation semiconductors for use in power devices. However, SiC substrates are very difficult to machine because of their mechanical hardness and marked chemical inertness. We developed a specular surface processing technology for super-high-hardness materials, such as a diamond and SiC. The new processing method uses a photochemical reaction for mechanical removal induced by ultraviolet ray irradiation. Here, we report a series of processes involved in final processing by UV-assisted polishing from pre-processing diamond lapping, to the SiC substrate with a 2-inch As-slice face. Pre-processing was performed with two steps of diamond lapping, which made a field with flatness of about 1μ m and a smooth surface of Ra 0.5 nm within 1 h from an As-slice face. By UV-assisted polishing, we were able to make a smooth surface of Ra 0.19 ? 0.28 nm and Rz 2.12 - 3.00 nm on the whole substrate, with a removal rate of 256 nm/h.

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In this study, the effects of fine particle peening (FPP) using SKH59 particles on Ni ion elution behavior of Ni-Ti alloy were investigated. FPP-treated specimens showed less Ni ion elution in comparison to polished and conventional shot-peened specimens. This was because an amorphous structure was formed on the surface of Ni-Ti alloy by FPP. The amount of Ni ion elution from the FPP-treated specimens was almost the same as that in oxidized specimens with a Ni-free surface layer. To investigate the possibility of applying FPP-treated Ni-Ti alloy to biomaterials, electrochemical corrosion tests and cell culture tests were also performed. FPP was shown to improve the corrosion resistance of Ni-Ti alloy in the passive region, but did not improve pitting corrosion resistance or cell compatibility.

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The TiAlN/AlCrN coating film deposited by AIP (Arc Ion Plating) is applied to the end mills and some types of such tools are used in dry milling of SUS304. The structure of TiAlN/AlCrN consists of a TiAlN layer and AlCrN layer. This coating film was designed to improve mechanical properties. The scratch test revealed that the exfoliation load of TiAlN/AlCrN film is higher than a monolayer of AlCrN, and has high adhesion with base material. On heating test of coating films, the TiAlN/AlCrN film shows high hardness of 20 GPa or more after heating to 1000°C. This temperature is 200°C higher than that of TiAlN coating film. Long tool life is obtained with these TiAlN/AlCrN-coated tools compared to ordinary TiAlN-coated tools and AlCrN-coated tools.

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