Co-Cr alloys such as L605 are widely applied for the manufacture of medical devices, including tiny cardiovascular stents. The presence of potentially toxic and allergenic release of Ni, Co, and Cr ions from these devices remains an unsolved concern. Surface modification by oxygen plasma immersion implantation (PIII) could be an excellent technique to create a dense and thin passive oxide layer on a relatively complex shape of a tiny device, such as a stent, thus reducing the potential release of metallic ions. The effect of oxygen PIII was investigated on L605 alloy specimens, from 5 to 50 mTorr gas pressures, and under pulsed bias voltages from −0.1 to −10 kV. The surface chemistry was investigated by x-ray photoelectron spectroscopy, while its morphology and surface energy were evaluated, respectively, by atomic force microscopy and scanning electron microscopy and by a sessile drop static contact angle. Electrochemical characterization was performed by potentiodynamic tests in the saline solution. Mechanical properties of the modified surface layer, specifically film adhesion and hardness (H), were assessed by scratch and nanoindentation tests. Results shown that the oxidized layers were composed of a mixture of Co and Cr oxides and hydroxides and were rich in Co. The corrosion rate was considerably reduced after O PIII, even for treatments using low bias voltage (−0.1 kV) and with consequent low oxygen implantation depth. Moreover, O PIII also improved surface hardness. The oxidized layers were found to have good adhesion and to be scratch resistant.

中文翻译：

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用于生物医学应用的钴铬合金上的等离子体浸没离子注入表面氧化。

L605 等 Co-Cr 合金广泛用于制造医疗器械，包括微型心血管支架。从这些设备中释放出的 Ni、Co 和 Cr 离子存在潜在的毒性和致敏性，这仍然是一个悬而未决的问题。通过氧等离子体浸入注入 (PIII) 进行表面改性可能是一种极好的技术，可以在相对复杂的微型设备（例如支架）上形成致密且薄的钝化氧化层，从而减少金属离子的潜在释放。在 5 至 50 mTorr 气压和 -0.1 至 -10 kV 的脉冲偏置电压下，研究了氧 PIII 对 L605 合金样品的影响。通过 X 射线光电子能谱研究表面化学，同时分别评估其形态和表面能，通过原子力显微镜和扫描电子显微镜以及静滴静态接触角。电化学表征通过在盐水溶液中的动电位测试进行。改性表面层的机械性能，特别是薄膜附着力和硬度（H），通过划痕和纳米压痕测试进行评估。结果表明，氧化层由 Co 和 Cr 氧化物和氢氧化物的混合物组成，并且富含 Co。 O PIII 后腐蚀速率显着降低，即使对于使用低偏置电压 (-0.1 kV) 的处理，随后的低氧注入深度。此外，O PIII 还提高了表面硬度。发现氧化层具有良好的附着力并且是抗划伤的。