LAUSR

Carbonated hydroxyapatite (CHA) coatings were deposited onto 316L stainless steel substrates using an in-house developed warm spraying system. Microstructures of the coatings were comprehensively investigated. Microhardness, tensile strength and wear resistance of the CHA coatings were examined. In addition, bioactivities of the coatings were studied after immersing in simulated body fluid (SBF). Results show that the as-sprayed coatings exhibited typical lamellar architectures consisting of partially melted and flattened splats, i.e., with molten shells and un-molten cores of original powders. The CHA coatings had nearly identical Ca/P ratios, crystalline structures and phase constitutions to those of the feedstock powders, indicating that undesired decompositions caused by overheating can be avoided by employing the warm spraying process. Microhardness and tensile strength of as-sprayed coatings were around 690 and 11.4-20.6 MPa, respectively. Moreover, the warm-sprayed CHA coating exhibited a high resistance against abrasion wear when sliding took place with polymers. After being immersed in Hank’s SBF for 28 and 60 days, new apatite was formed on the coating surface corroborating the good biocompatibility of the coating.