磁性固位体耐蚀性能的研究

目的研究3种钕铁硼磁性固位体的外包裹容器不锈钢的耐腐蚀性能.方法将3种磁性固位体分别浸泡于人工唾液中,温度为36.5℃,时间为6个月.实验方法包括恒电位法极化曲线试验与浸泡试验,分析材料的耐腐蚀能力.结果极化曲线中,国产衔铁的自腐蚀电流密度为7.015μA/cm2,国产磁体为0.119μA/cm2.浸泡试验中,国产衔铁的腐蚀速度为3.67×10-5mg/cm2*h,国产磁体的腐蚀速度为1.77×10-5mg/cm2*h.国产磁性固位体与进口同类材料相比,其耐腐蚀性能差异无显著性.结论人工唾液环境会使3种磁性固位体的耐腐蚀能力降低,进而缩短其寿命.

An evaluation on corrosion resistance of magnetic retainers

OBJECTIVE: The present study was to explore the corrosion resistance of three kinds of magnetic retainers which named neodymium-iron-boron magnet and encapsulated in stainless steel. METHODS: Three kinds of magnetic retainers were exposed for 6 months to artificial saliva thermostated at 36.5 degrees C. This study included a electrochemical test as polarization curves and a chemical test as immersion test. RESULTS: In the electrochemical test, current density of the national keeper was 7.015 microA/cm2 and magnet was 0.119 microA/cm2. In the chemical test, corrosion rate of national keeper was 3.67 x 10(-5) mg/cm2.h and magnet was 1.77 x 10(-5) mg/cm2.h. The corrosion resistance of the national magnetic retainer had little difference with the imported ones. CONCLUSION: Transient exposure of stainless steel to artificial saliva environment is likely to significantly increase elemental release. It would affect the useful life span of magnets.