Synthesis of Fe–Ni–B–Si–Nb amorphous and crystalline composite coatings by laser cladding and remelting

Amorphous and nanocrystalline composite coatings are synthesized by laser cladding and remelting. The result of X-ray diffraction shows that an amorphous structure and some crystalline phases occur in the coatings. The microstructure of the coatings is different with different amounts of Si in the coatings. The fracture appearance suggests that brittle fracture occurs in coatings. There are some oxides, borides and metal compounds appearing on the surface of Fe32Ni32Si16B18Nb2 and Fe30Ni30Si20B18Nb2 coatings. The abrasion resistance of the coatings will be improved with the increase of amorphous phases. The coatings along the depth direction can be divided into three regions which are an amorphous and crystalline composite layer, a clad layer and a diffusion layer, respectively. The experiments show that Si plays a critical role in fabricating a Fe-based amorphous composite coating.