形变医用镍钛合金表面TiN涂层耐蚀性的研究

Study on Corrosion Resistance of TiN Coated Biomedical Nitinol under Deformation

在37℃的人造血浆中,研究了有无TiN涂覆层的镍钛合金的耐蚀性。电化学实验显示TiN涂层能使其相对饱和甘汞电极的电位从0.95 V增至1.5 V,其腐蚀电流密度从0.20 mA/cm2降至0.10 mA/cm2。溶解的钛离子和镍离子的化合价为正二价。变形量小于6%时,镍钛基TiN膜层的耐蚀性并未受到严重影响。由于变形产生的TiN膜层裂纹而导致了轻微的腐蚀,但其耐蚀性仍好于没有TiN膜层的镍钛合金,因为在裂纹处未观察到电偶腐蚀。

The corrosion resistance of nitinol with and without a titanium nitride coating is electrochemically investigated at 37 ℃ in artificial plasma. The electrochemical experiments show that the titanium nitride （TiN） coating can increase the stable potential from 0.95 V to 1.5 V versus a saturated calomel electrode and reduce the corrosion current density from 0.20 mA/cm^2 to 0. 10 mA/ cm^2. The valence of the dissolved titanium and nickel ions is plus two. At deformation less than 6%, no significant negative effects on the corrosion resistance of the TiN coated nitinol is observed. More deformation causes cracks in the TiN coatings and consequently, the corrosion resistance degrades slightly, but it is still better than that of the uncoated nitinol since no galvanic corrosion is observed from the broken areas.