減圧プラズマ溶射法による TiB2 分散 Fe-Cr複合皮膜の作製とその特性評価

MMC (Metal Matrix Composite) has been focused in recent years due to its high strength and wear resistance. Among the dispersion materials of MMC, Titanium Boride (TiB2) exhibits attractive properties in terms of high stiffness, high hardness and high corrosion resistance. Therefore, it can be used as protection coating of the structural components according to fabrication of thick coatings. In this study, fabrication of TiB2 dispersed Fe-Cr composite coatings was carried out by MA (Mechanical Alloying) method and LPPS (Low Pressure Plasma Spray). It was possible to fabricate TiB2 dispersed Fe-Cr powders by MA method. Furthermore, the thermal sprayed coatings sustained the dispersion structure. Micro Vickers hardness of the coatings increased with the TiB2 concentration in the coatings. However, FeCr-50 wt.% TiB2 exhibited quite low hardness. It was considered that the excess TiB2 made the microstructure of the coating porous. Therefore, fabrication of high hardness TiB2 dispersed Fe-Cr coatings was possible according to the selection of moderate TiB2 mixing ratio.