Research on the fabrication of bioceramic composite coatings fabricated by Nd-YAG laser cladding

摘要

Laser surface cladding is a material processing technique to overlay the precursor material with the substrate to form a sound chemical and metallurgical bonding. Recently, laser cladding technique has been introduced in the bioceramic coating field. This paper presents a new technology to obtain bioceramic composite coating on Ti6Al4V substrate by Nd-YAG laser cladding. The microstructures of the mixed powders and cladding layer were investigated by scanning electron microscopy, and the compositions were analyzed by electron diffraction spectroscopy. The phases of the mixed powders and cladding layer were clarified by X-ray diffraction technology. Composite coating including HAP，Ca_2P_2O_7, Ca_3(PO_4)_2 and calcium titanates was successfully obtained by Nd-YAG laser cladding with pre-depositing mixed powders of CaHPO_4·2H_2O and CaCO_3 directly on Ti6Al4V substrate. The average grain size of the mixed powders is 3μm from the image analyse software. The most important parameter that affected the completion of laser cladding was the scanning speed.