医用不锈钢表面沉积类金刚石薄膜的电化学腐蚀性能研究

ELECTROCHEMICAL CORROSION BEHAVIOR OF AMORPHOUS DIAMOND-LIKE CARBON FILM COATED BIOMEDICAL STAINLESS STEEL

医用316L不锈钢植入物植入体内后,体内环境可导致其产生腐蚀和Ni离子的析出。利用双放电腔微波等离子体源全方位离子注入设备,采用等离子体源离子注入(plasmasourceionimplantation,PSII)和等离子体增强化学气相沉积(plasmaenhancedchemicalvapordeposi tion,PECVD)复合工艺在医用316L不锈钢表面沉积类金刚石薄膜,进行表面改性,以提高其在模拟体液环境中的腐蚀阻抗。扫描电子显微镜和原子力显微镜观察发现,薄膜由纳米粒子构成,膜层连续光滑。电化学腐蚀测试表明:采用PSII+PECVD复合工艺制备的类金刚石薄膜与316L不锈钢改性体系在(37±1)℃的Troyde’s模拟体液中的自腐蚀电位约为120mV,体系的击穿电位超过1.9V,与基体316L不锈钢相比,其热力学稳定性与抗腐蚀性能得到增强,改性效果优于单独的PECVD工艺。

The corrosion-resistance performance is one essential factor to determine the biocompatibility of metal implants. The corrosion and nickel-releasing may appear in body environment for the implants made by biomedical 316 L stainless steel after implanted. Diamond-like carbon films were synthesized from methane on biomedical stainless steel by use of the hybrid plasma source ion implantation (PSII) and plasma enhanced chemical vapor deposition (PECVD) technologies, through twinned microwave electron cyclotron resonance (ECR) plasma source enhanced ion implantation system in order to improve the corrosion resistance in simulated body fluid. The observation of scanning electron microscopy (SEM) and atomic force microscopy (AFM) photographs shows that diamond-like carbon films consisting of nano-particles are continuous and smooth. The results of electrochemical corrosion tests indicate that diamond-like carbon films prepared by the hybrid PSII and PECVD technologies have a better corrosion-resistance performance compared with biomedical 316 L stainless steel. The free corrosion potential in Troyde's simulated body fluid of (37 ± 1)°C is 120 mV and the breakdown potential is more than 1.9 V. The thermodynamic stability and corrosion performance is prior to that of the sample coated by PECVD.