类金刚石薄膜在模拟体液中的电化学阻抗

利用双放电腔微波等离子体源全方位离子注入设备，分别采用等离子体增强化学气相沉积技术、等离子体源离子注入和等离子体增强化学气相沉积复合技术两种工艺对医用3161，不锈钢进行类会刚石薄膜表面改性。利用电化学阻抗谱法考察了两种工艺制备的类金刚石薄膜在模拟体液中的抗腐蚀性能。结果表明：与采用等离子体增强化学气相沉积技术制备的类金刚石薄膜相比，在72h的浸泡时间内，采用等离子体源离子注入和等离子体增强化学气相沉积复合技术制备的类金刚石薄膜防腐蚀性能明显增高，腐蚀阻抗较高，碳注入层可有效抑制溶液渗入薄膜和基体之间的界面，起到了腐蚀防护层的作用。动电位极化测试表明：采用复合技术制备的类金刚石薄膜在模拟体液中的腐蚀倾向性更低，钝态稳定性更好。

ELECTROCHEMICAL IMPEDANCE SPECTROSCOPY DIAGNOSIS OF DIAMOND-LIKE CARBON COATINGS IN SIMULATED BODY FLUID

Diamond-like carbon(DLC) coatings used in biomedical fields were deposited on 316L stainless steel by plasma enhanced chemical vapor deposition(PECVD),hybrid plasma source ion implantation(PSII) and PECVD respectively.The corrosion behavior of DLC coatings prepared by different methods was investigated in approximately neutral simulated body fluid by electrochemical impedance spectroscopy(EIS) measurement.The results show that the DLC coatings by a hybrid PSII and PECVD technique are more compact than those by the PECVD technique and have greater corrosion resistance during an immersion period of 72 h.The new technique is effective for the carbon implantation layer to prevent the electrolyte from penetrating into the interface between the coating and the substrate,acting as a protective layer from corrosion.The potential-dynamic polarization measurements also indicate that the DLC coatings prepared by the hybrid PSII and PECVD technique have less tendency towards corrosion and better passivation stability.