Abstract

Single NbSi₂ and duplex NbSi₂/Nb₅Si₃ coatings were successfully applied on Nb substrates using halide activated pack cementation (HAPC) method at 1100 and 1300°C, respectively. Duplex NbSi₂/Nb₅Si₃ coating with Nb₅Si₃ inner barrier layer, higher thickness, and lesser micro-cracks considerably decreased the infiltration of simulated body fluid (SBF) solution. This deduction was pertained to the high corrosion potential and lowest corrosion current density for the NbSi₂/Nb₅Si₃ coated Nb alloy in corrosive solution. The Nb₅Si₃ inner barrier layer can protect the Nb substrate from corrosive solution when it passes through from NbSi₂ top layer. Moreover, higher charge transfer resistance (R_ct), impedance modulus at a low-frequency (\(\left| Z \right|\)) and phase angle were also observed for the duplex NbSi₂/Nb₅Si₃ coated Nb alloy. On the other hand, in vitro bioactivity test indicated higher capability of apatite formation on the silicide coatings compared to uncoated Nb substrate in SBF solution. In fact, modification of chemical composition and surface morphology of Nb substrate surface can provide suitable nucleation sites for apatite formation and growth in SBF solution.

中文翻译：

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Nb基体上单一NbSi 2和NbSi 2 / Nb 5 Si 3双层涂层在生物医学应用中的腐蚀行为和体外生物活性的研究

摘要

分别在1100和1300°C下使用卤化物活化包胶结（HAPC）方法将NbSi ₂单层和NbSi ₂ / Nb ₅ Si ₃双相涂层成功地涂覆在Nb基底上。具有Nb ₅ Si ₃内阻挡层的双层NbSi ₂ / Nb ₅ Si ₃涂层，较高的厚度和较小的微裂纹大大降低了模拟体液（SBF）溶液的渗透。这种推论是关于在腐蚀溶液中涂覆NbSi ₂ / Nb ₅ Si _3的Nb合金的高腐蚀电位和最低腐蚀电流密度。铌₅ Si ₃内阻挡层可以保护Nb衬底从NbSi ₂顶层穿过时不受腐蚀溶液的侵蚀。此外，双相NbSi ₂ / Nb ₅ Si ₃还观察到较高的电荷转移电阻（R _ct），低频下的阻抗模量（\（\ left | Z \ right | \））和相角。涂层的Nb合金。另一方面，体外生物活性测试表明，与SBF溶液中未涂覆的Nb基材相比，硅化物涂层上形成磷灰石的能力更高。实际上，改变Nb衬底表面的化学组成和表面形态可以为SBF溶液中磷灰石的形成和生长提供合适的成核位点。