Dealloying and electroformation in high-Pd dental alloys.
Dealloying and electroformation in high-Pd dental alloys.
复制标题
高钯牙科合金的脱合金和电铸。
DOI：
10.1016/s0109-5641(00)00045-2
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发表时间：
2000
期刊：
影响因子：
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通讯作者：
Prasad,A
中科院分区：
文献类型：
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作者：
Sarkar,NK;Berzins,DW;Prasad,A
目的高钯牙科合金的腐蚀与脱合金和电铸有关，具体取决于合金的组成。方法研究两种商用高钯合金Naturelle(79Pd-10Cu-2AU-9Gawt%)和Rx 91(54Pd-37Ag-9Sn)及其元素组分在磷酸盐缓冲盐水(PBS)中的腐蚀特性。铟是高钯合金中的一种常见元素，也包括在内。测量了每种材料的腐蚀特性：24小时开路电位(OCP)和动电位极化曲线。用X射线光电子能谱(XPS)对两种合金在PBS中浸泡2个月前后的表面成分进行了分析。结果在纯金属中，Ga的电活性最高，其次是In、锡、铜、银、金、钯。阳极极化数据显示，所有贱金属在PBS中都是不稳定的。在纯Ag的极化曲线上证实了AgCl的电生成过程。PdCu基合金的两种电化学性能都与纯Pd非常相似。PdAg基合金表现出与银相似的腐蚀行为。XPS数据表明，PdCu基合金的腐蚀与表面铜和镓含量的减少以及钯和金含量的增加有关。在腐蚀过程中，PdAg基合金表面的锡含量减少，银含量增加，钯含量没有变化。PdCu基合金的行为归因于电偶相互作用的运行，该作用导致贱金属溶解，表面主要是Pd的浓缩。脱合金化、富银和氯化银的形成被认为是导致观察到的PdAg基合金行为的原因。这些机制与已发表的离子释放研究数据一致。意义任何Pd合金的致敏潜力取决于其形成富Pd表面从而释放Pd+2离子的倾向。目前的研究虽然有限，但已经表明，电化学特征，即OCP和极化曲线，可以用来识别这种合金。有必要进行进一步的研究，以评估这些特征在区分生物安全的钯合金和不安全的钯合金方面的广泛适用性。
ObjectiveThe corrosion of high-Pd dental alloys, depending on their composition, is postulated to be associated with dealloying and electroformation. The aim of this study was to obtain additional information to support these postulations.MethodsThe corrosion characteristics of two commercial high-Pd alloys, Naturelle (79Pd–10Cu–2Au–9Gawt%) and Rx 91 (54Pd–37Ag–9Sn), and their elemental components were evaluated in a phosphated buffer saline (PBS) solution. Indium, a common element in high-Pd alloys, was also included. The corrosion characteristics measured for each material were the 24h open circuit potential (OCP) and the potentiodynamic anodic polarization curve. Additionally, the surface composition of the two alloys, before and after immersion corrosion in PBS for 2months, was analyzed by X-ray photo electron spectroscopy (XPS).ResultsOf the pure metals, Ga had the most electroactive OCP followed in order by In, Sn, Cu, Ag, Au, and Pd. The anodic polarization data showed all base metals to be unstable in PBS. The electroformation of AgCl was evidenced in the polarization curve of pure Ag. Both electrochemical characteristics of the PdCu-based alloy were very similar to that of pure Pd. The PdAg-based alloy displayed corrosion behavior resembling that of Ag. XPS data showed that the corrosion of the PdCu-based alloy was associated with a decrease in surface content of Cu and Ga but an increase in Pd and Au. The PdAg-based alloy surface during corrosion showed a decrease in Sn, an increase in Ag, and an unaltered Pd content. The behavior of the PdCu-based alloy is attributed to the operation of a galvanic interaction that causes dissolution of base metals and surface enrichment with primarily Pd. Dealloying, Ag-enrichment, and AgCl formation are thought to have contributed to the observed behavior of the PdAg-based alloy. These mechanisms are consistent with data from published ion release studies.SignificanceThe allergenic potential of any Pd alloy is dependent on its propensity to develop a Pd-rich surface and thus release Pd+2ions. The present study, though limited, has shown that electrochemical characteristics, namely OCP and polarization curves, can be used to identify such alloys. Further studies are warranted to evaluate the widespread applicability of these characteristics in distinguishing between Pd alloys that are biologically safe and those that are not.