Study on Biocompatibility of CoCrMo Alloy Parts Manufactured by Selective Laser Melting
The biocompatibility of implant is generally believed to be an important factor affecting the operation success and service life of implant, the biocompatibility study of CoCrMo alloy fabricated by selective laser melting (SLM) method thus becomes the key for the successful application of personalized implant. We determined both the blood compatibility and the release rate of ions of SLM-manufactured and cast CoCrMo alloy implants following submersion in various corrosive solutions. The surface structure and morphology of the samples before and after the experiment were investigated to ascertain the mechanisms of ion release and blood compatibility. The results indicated that the concentrations of Co and Cr ions of the SLM-manufactured parts after incubation in the different corrosive liquids were less than that of the cast parts, in which increased roughness presented greater potential for Co ion release compared to surfaces with low roughness. Variation in density did not apparently impact the release of Co ions under a certain threshold, while the release of Cr ions was dependent on the degree of polishing and density. The hemolysis ratio of the SLM-manufactured parts was 41.21% lower than that of cast parts, and the consumption rates of leukocytes, erythrocytes, hemoglobin and platelets due to the SLM-manufactured parts were 13.1, 40, 69.6 and 60.8% lower than that of cast parts, respectively. The SLM-manufactured parts demonstrated a more uniform surface structure with fewer pores than that of the cast parts, thus providing basis for the application of SLM CoCrMo alloy in medical.