氟处理对AZ31B镁合金生物耐蚀降解行为的影响

Effect of Fluoride Conversion Treatment on Bio-Corrosion Behavior of AZ31B Magnesium Alloy

摘要:

采用低温化学方法在AZ31B镁合金表面制备出氟涂层，并研究了涂层的表面特征，氟处理后AZ31B镁合金在模拟体液中的腐蚀行为。结果表明，氟涂层均匀致密，与基体结合良好。经氟处理后的AZ31B镁合金的耐蚀性能有较大提高，其在模拟体液中的降解缓慢，合金浸泡后溶液的pH值保持在7.5~8.8之间，有效降低了合金降解而引起的碱性增强趋势。氟涂层在模拟体液中会逐渐转化为Ca3(PO4)2，新生成的表面膜会继续起到保护合金基体的作用。

Abstract:

Fluoride-coating was prepared on AZ31B magnesium alloy by an immersion treatment in hydrofluoric acid at room temperature, and the surface morphology, composition, corrosion resistance and degradation mechanism of the coated alloy were studied. The results show that the conversion coating is compact with good bonding to the alloy. The corrosion resistance of the fluoride coated AZ31B alloy is obviously improved, and its degradation in simulated body fluid (SBF) is slow. The pH value of the SBF (the coated alloy immersed in) keeps in a range of 7.5 to 8.8, which can effectively reduce the alkalization caused by the biodegradation of the alloy. The fluoride coating gradually transform into Ca3(PO4)2 in SBF, which will continue protect the alloy from the corrosion.