Study on deposition of biomedical Ta coating on Ti6Al4V alloy substrate by CVD and its properties

With superior bone growth and integration abilities, porous tantalum (Ta) implants prepared by depositing Ta coating on foam carbon have been widely used in clinical for two decades. To solve their high cost and high weight disadvantages, the deposition of thin Ta coating on porous titanium (Ti) alloys substrate by chemical vapor deposition (CVD) is expected to be a promising strategy. However, until now realizing the novel strategy is still a big challenge. In this study, by the TaCl5-H2 reaction, we investigated the preparation of Ta coating on Ti6Al4V (TC4) matrix by CVD. The effects of reaction temperature and gas flow on the microstructure, composition, and properties of the Ta coating were systematically investigated. The results indicated that Ta coatings about 5 mu m with high quality was successfully prepared on plane and porous TC4 for the first time, and the reaction temperature played a more important role than the gas flow. The optimal preparation parameters were determined to be 950 degrees C and 200 sccm. Under the condition, Ta coating with the fully alpha-Ta phase, high purity, high uniformity and compactness was achieved. The Ta coating exhibited excellent binding force, corrosion resistance, hydrophilicity. Through eliminating the toxic V ions dissolution from TC4, the Ta coating also obtained excellent cell compatibility, which is meaningful for porous TC4 implants widely used in clinic with very high specific surface area. Therefore, this research evidenced that, by CVD, the novel thin Ta coated porous TC4 implants with lower cost, lower weight and higher biocompatibility could be achieved.