Erosion behavior of arc sprayed FeTi/CrB MMC coating at elevated temperature

• A novel powder cored wire is developed to prepare the FeTi/CrB coating.
• FeTi/CrB coating is a typical MMC coating reinforced by ceramic particles.
• Compared with SH-SAM coating, FeTi/CrB coating has a lower porosity and higher bond strength.
• FeTi/CrB coating exhibits excellent high temperature erosion resistance.
• High temperature erosion mechanism of FeTi/CrB coating is proposed.

A self-developed FeTi/CrB composite cored wire and the commercially available stainless amorphous metal (SH-SAM) cored wire were used to form the composite coatings by arc spraying on 20 g steel substrates. The coating composition and microstructure were characterized by energy dispersive X-ray spectra, X-ray diffraction and scanning electron microscope. The high temperature erosion properties of FeTi/CrB and SH-SAM coatings were determined at different impact angles and environmental temperatures. The results show that the matrix phase of FeTi/CrB coating consists of FeCr solid solution, with a certain amount of oxide inclusions and boride hard phase, forming a metal matrix composites (MMC) coating reinforced by ceramic particles. Compared with the SH-SAM coating, the FeTi/CrB coating has lower porosity and higher bond strength. The high temperature erosion rate of FeTi/CrB coating is much lower than that of SH-SAM coating at all experimental conditions. The FeTi/CrB coating exhibits good toughness and high spalling resistance attributed to the hard phase at elevated temperature. By contrast, the SH-SAM coating presents more brittle characteristics. The FeTi/CrB MMC coating presents itself as a potential protective coating for circulating fluidized bed boiler.