pH值对磁性固位体耐蚀性能的影响

目的　研究人工唾液的酸碱度在偏酸性的条件下,3种磁性固位体外包裹容器的耐腐蚀能力的改变。方法　将3种磁性固位体浸泡于人工唾液中,介质pH值分为5·6和7·0两组,实验温度36·5℃,时间6个月。采用恒电位法测定极化曲线实验、浸泡实验及扫描电镜方法,分析材料的耐腐蚀能力。结果　pH值下降,磁性固位体外包裹容器---不锈钢中铁离子的溶出量提高近10倍。表明在偏酸性的环境中,3种材料的腐蚀速度都加快。结论　磁性固位体的耐酸性能力相对较差,这将影响他们的使用寿命。

The Effects of pH in Artificial Saliva on the Corrosion Resistance of Magnetic Retainers

OBJECTIVE: The aim of this article was to discover the corrosion resistance of magnetic attachments, which were encapsulated in stainless steel, when pH value of artificial saliva was lower than normal. METHODS: Three kinds of magnetic retainers were exposed for 6 months to artificial saliva with pH ranging from 5.6 to 7.0, thermostated at 36.5 degrees C. This study included electrochemical test as polarization curves, chemical test as immersion test and SEM to analyze the corrosion behavior of the materials. RESULTS: Fe3+ ions in stainless steel released more than ten times in an environment pH 5.6 than pH 7.0. The higher concentration of H+, the more elemental release. That pH value of artificial saliva reduced may affect the corrosion speed. The magnetic retainers were not resistant to acidic environments during exposure. CONCLUSION: Transient exposure of stainless steel to an acidic oral environment can increase elemental release significantly. So acid resistance of magnetic retainers was relatively weak, and it would affect the life span of magnets.