Laser producing particulate reinforced Fe-based MMC coatings and industrial applications

This paper presents the research achievements on Fe-based metal matrix composite coatings (MMC) on steel and iron substrates by laser alloying and laser cladding and their industrial applications. The high carbon-equivalent design ensures the good formability and high hardness while eliminates hot cracking during rapid solidification. The jointly adding of strong-carbide-formation-elements promotes the precipitation of large quantity of hard particles. The typical microstructure of the MMC coating characterizes about 4000∼5000/mm² carbide particles (1∼3 micron in diameter) homogeneously precipitated on iron-base matrix. The average hardness of the coating reaches up to Hv_0.2 950∼1050. Tribological test proved that this particulate reinforced Fe-based MMC coating posses excellent wear resistance and couple ability with various different frictional counterparts as well as remarkable decrease of the friction coefficient. Its grain-abrasion resistance is better than that of the plasma sprayed Mo coating and its adhesive-abrasion resistance better than the chromium coating. This MMC coating also demonstrated unique corrosion resistance and contact-fatigue resistance. This particulate reinforced MMC coatings have been successfully applied in rock arms, cam shafts, piston rings of engine, plunger pistons and kerf of cutting knives.