Study of TiB₂ particles enhanced metal matrix composited(MMC) coatings

Four kinds of TiB₂ particles enhanced metal matrix composited coatings(MMC) were prepared by cored wires produced with addition of pretreated TiB₂-based ceramic powders and arc spraying.Microstructure of arc sprayed NiCr-TiB₂,304L-TiB₂,NiCr-TiB₂/Al₂O₃ and 304L-TiB₂/Al₂O₃ coatings were detailedly investigated by optic microscope,scan electron microscope(SEM) and transmission electron microscope(TEM).Experimental results showed that metallic phases in MMC coatings were typical column crystal that presented rapid solidification microstructure characteristics,and dislocation existed in matrixes.The coatings presented similar lamellar structure,but ceramic particle shape,distribution and bonding with metallic phase exhibited differences.