Electrochemical characterization of cast titanium alloys
Electrochemical characterization of cast titanium alloys
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DOI：
10.1016/s0142-9612(02)00293-4
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发表时间：
2003-01-01
期刊：
影响因子：
14
通讯作者：
Okabe, T
中科院分区：
文献类型：
--
作者：
Cai, Z;Shafer, T;Okabe, T
由于熔融金属与熔模的反应，在铸造钛合金表面形成反应层。该表面层可能会影响合金在口腔环境中的腐蚀。本研究的目的是表征铸造钛合金的体外腐蚀行为。 ASTM Grade 2 CP 钛、Ti-6Al-4V、Ti-6Al-7Nb 和 Ti-13Nb-13Zr 合金被铸造成 MgO 基熔模。对具有三种表面条件的铸件（N = 4）进行实验：（A）喷砂后的铸态表面，（B）去除反应层后的抛光表面，以及（C）去除反应层后的喷砂表面。开路电位（OCP）测量、线性极化和动电位阴极极化在37℃的充气（空气+10％COD改性Tani-Zucchi合成唾液）中进行。随后在实验前和实验期间用N-2 + 10％CO 2 气体脱气2小时的相同介质中进行动电位阳极极化。计算极化电阻（R-P）和腐蚀速率（I-CORR）。数值结果在 α = 0.05 后对所有样品进行了稳定化。在所有金属的不同表面之间观察到了钝化区域，然后在表面 A 和 C 上观察到了钝化区域。在具有表面 B 的所有金属上观察到了广泛的钝化区域。所有金属中三个表面的 OCP、R-P、I-CORR 或击穿电位。Mann-Whitney 测试显示，与其他表面相比，表面 C 的 R-P 值明显较低，而 I-CORR 值较高。结果表明，在口腔的氧化电位范围内，所有检查的金属/表面组合均表现出优异的耐腐蚀性。
A reaction layer forms on cast titanium alloy surfaces due to the reaction of the molten metal with the investment. This surface layer may affect the corrosion of the alloy in the oral environment. The objective of this study was to characterize the in vitro corrosion behavior of cast titanium alloys. ASTM Grade 2 CP titanium, Ti-6Al-4V, Ti-6Al-7Nb and Ti-13Nb-13Zr alloys were cast into a MgO-based investment. Experiments were performed on castings (N = 4) with three surface conditions: (A) as-cast surface after sandblasting, (B) polished surface after removal of the reaction layer, and (C) sandblasted surface after removal of the reaction layer. Open-circuit potential (OCP) measurement, linear polarization, and potentiodynamic cathodic polarization were performed in aerated (air+ 10% COD modified Tani-Zucchi synthetic saliva at 37degreesC. Potentiodynamic anodic polarization was subsequently conducted in the same medium deaerated with N-2 + 10% C02 gas 2 h before and during the experiment. Polarization resistance (R-P) and corrosion rate (I-CORR) were calculated. Numerical results were subjected to nonparametric statistical analysis at alpha = 0.05. The OCP stabilized for all the specimens after 6 x 10(4) s. Apparent differences in anodic polarization were observed among the different surfaces for all the metals. A passivation region followed by breakdown and repassivation were seen on specimens with surfaces A and C. An extensive passive region was observed on all the metals with surface B. The Kruskal-Wallis test showed no significant differences in OCP, R-P, I-CORR or break down potential for each of the three surfaces among all the metals. The Mann-Whitney test showed significantly lower R-P and higher I-CORR values for surface C compared to the other surfaces. Results indicate that the surface condition has more effect on corrosion of these alloys than the surface reaction layer. Within the oxidation potential range of the oral cavity, all the metal/surface combinations examined showed excellent corrosion resistance. (C) 2002 Elsevier Science Ltd. All rights reserved.