材料期刊网

为了降低AZ91D镁合金活泼的化学性质,使其成为耐蚀性更好的医用金属材料,在不同pH值及反应温度等条件下对AZ91D镁合金进行钝化,观察了不同条件下制备的膜层的表面形貌、元素构成,并测试了其电化学性质,研究了磷化的pH值和温度对磷化膜性能的影响.结果表明:磷化液的温度及pH值对磷化膜性能有重要影响,当pH值为2.8,温度为40℃时,制备的磷化膜为针状鳞片、尺寸均一,膜层覆盖最为致密细腻,表面膜层中主要生成了CaHPO4·2H2O化合物,即DCPD,还有少量Ca3(PO4)2,膜层在AZ91D表面形成了稳定的钝化层,有效降低了其化学活泼性,大幅提高了其耐蚀性.

To reduce the active chemical properties of AZ91D magnesium alloy and make it become a better material for medical use,the pas sivation treatment of AZ91D magnesium alloy was carried out under different bath pH value,reaction temperature and other conditions.The surface morphology and composition of the coatings under different conditions were investigated and the electrochemical properties were evaluated.Besides,the effects of pH value and temperature on the coating properties were studied.Results showed that the temperature and pH value of phosphating solution greatly influenced the coating properties.When the pH value was 2.8 and the temperature was 40 ℃,the obtained films had acicular scales and uniform size,and the film coverage was the most compact.The main formation of the coating was CaHPO4 · 2H20 compounds (DCPD),and there was also a small amount of Ca3 (PO4) 2 in the coating.The good stable passivation layer on the surface was formed,effectively reducing the chemical activity,and increasing the corrosion resistance.