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所属单位：材料科学与技术学院

发表刊物：ACTA METALLURGICA SINICA

关键字：Ta-N coating Ti-6Al-4V alloy electrochemical corrosion passive film semiconductor property

摘要：Due to its combination of outstanding characteristics, such as superior biocompatibility, excellent mechanical properties as well as good corrosion resistance, Ti-6Al-4V alloy has gained much attention as one of the most popular load-bearing biomedical metals in the area of orthopedic and dental. Unfortunately, Ti-6Al-4V alloy suffers from the localized corrosion damage in human body fluids containing high chloride ion concentrations, which leads to the release of metal ions into the human body. The released ions (e.g., Al and V) are found to not only cause allergic and toxic reactions but also exhibit potential negative effects on osteoblast behavior. To improve the corrosion resistance of Ti-6Al-4V alloy in simulated body fluids, a 40 mm thick Ta2N nanocrystalline coating with an average grain size of 12.8 nm was engineered onto a Ti-6Al-4V substrate using a double cathode glow discharge technique. The hardness and elastic modulus of the Ta2N coating were determined to be (32.1 +/- 1.6) GPa and (294.8 +/- 4.2) GPa, respectively, and the adhesion strength of the coating deposited on Ti-6Al-4V substrate was found to be 56 N. There is no evidence of crack formation within the coating under loads ranging from 0.49 N to 9.8 N, implying that the Ta2N nanocrystalline coating has a high contact damage resistance. Moreover, the corrosion resistance of the Ta2N nanocrystalline coating is significantly greater than that of Ti-6Al-4V alloy when tested in naturally aerated Ringer's solution at 37 degrees C. This is due to that the passive film developed on the coating has superior compactness compared with that formed on the uncoated Ti-6Al-4V alloy. XPS analysis indicated that at a low polarized potential, the passive film consisted of TaOxNy, which would be converted to Ta2O5 at a higher polarized potential. The analysis of Mott-Schottky curves suggested that the passive film formed on the coating exhibits n-type semiconductor properties and, as such, the density and diffusivity of carrier for the coating was considerably lower than that for the uncoated Ti-6Al-4V alloy.

ISSN号：0412-1961

是否译文：否

发表时间：2018-03-11

合写作者：Bao Xike,Jiang Shuyun

通讯作者：徐江