摘要
通过向Ni-P镀液中添加TiO2溶胶(2~11mL/L)的方法在AZ31B镁合金表面制备了Ni-P-TiO2复合镀层。用电化学方法评价了复合镀层在3.5%(质量分数)NaCl溶液中的腐蚀行为;用扫描电镜(SEM)、透射电镜(TEM)和X射线衍射仪(XRD)分析了Ni-P-TiO2复合镀层的微观形貌和显微组织结构;用维氏硬度仪测试了Ni-PTiO2复合镀层的显微硬度。结果表明:随着TiO2溶胶含量的增加,复合镀层组织中菜花状胞状颗粒的尺寸逐渐减小,硬度和耐蚀性均是先增大后减小;当TiO2含量为8mL/L时,镀层的结构致密,且无明显缺陷和裂纹产生,其显微硬度和耐蚀性均达到最高;Ni-P-TiO2复合镀层有明显的点蚀电位,说明镀层在腐蚀介质中形成了钝化层,对镁合金起到更好的保护作用。
Ni-P-TiO2 composite coatings were prepared on surface of AZ31 B magnesium alloy by adding TiO2 sol(2-11 mL/L)to Ni-P bath.The corrosion behavior of the composite coating in 3.5%(mass fraction)NaCl solution was evaluated by electrochemical method.The micro morphology and microstructure of the composite coatings were characterized by scanning electron microscopy(SEM),transmission electron microscopy(TEM)and X-ray diffraction(XRD).The microhardness of the composite coatings was tested by Vickers hardness tester.The results show that the size of cauliflower-like particles in microstruture decreased with raising the TiO2 sol content,and the microhardness and corrosion resistance increased first and then decreased.When the TiO2 sol content was 8 mL/L,the composite coating had a compact structure without obvious defects and cracks,and its microhardness and corrosion resistance hit the best values.The Ni-P-TiO2 composite coatings had obvious pitting potential,indicating that the coating had formed a passivation layer in the corrosive medium,which provided a better protective effect for magnesium alloy.
作者
宋佳文
王瑞红
SONG Jiawen;WANG Ruihong(School of Materials Science and Engineering,Xi′an University of Technology,Xi’an 710048,China)
出处
《腐蚀与防护》
CAS
北大核心
2020年第8期11-17,共7页
Corrosion & Protection
