镍钴纳米复合镀层在滨海盐土模拟溶液中的耐腐蚀性能

Corrosion resistance of Ni-Co nano-composite coatings in Binhai saline-soil simulation solution

为了提高45钢在盐土环境中的耐腐蚀性能,采用电沉积法在其表面制备了Ni-Co-Si_(3)N_(4)、Ni-Co-Al_(2)O_(3)和Ni-Co-Si_(3)N_(4)-Al_(2)O_(3)纳米复合镀层。利用扫描电镜(SEM)、X射线衍射仪(XRD)、能谱仪(EDS)对镀层的形貌、相结构和成分进行了表征和分析,并利用光学接触角测量仪和电化学工作站分别对镀层的润湿性及耐蚀性能进行了研究。结果表明:与Ni-Co-Si_(3)N_(4)和Ni-Co-Al_(2)O_(3)镀层相比,Ni-Co-Si_(3)N_(4)-Al_(2)O_(3)复合镀层表面晶粒相对细化,晶胞均匀致密,镀层平均晶粒尺寸最小,为19.20 nm;Ni-Co-Si_(3)N_(4)-Al_(2)O_(3)镀层表面静态接触角达到131.4°,表面疏水性最佳;电化学测试表明,在土壤模拟溶液条件下,Ni-Co-Si_(3)N_(4)-Al_(2)O_(3)镀层的自腐蚀电流密度和腐蚀速率分别为1.30μA·cm^(-2)和0.016 mm·a^(-1),电荷转移电阻为214.91 kΩ·cm^(-2),镀层具有更优的耐蚀性。

In order to improve the corrosion resistance of 45 steel in saline soil environment, Ni-Co-Si_(3)N_(4), Ni-Co-Al_(2)O_(3) and Ni-Co-Si_(3)N_(4)-Al_(2)O_(3) nano-composite coatings were prepared on its surface by electrodeposition. Morphology, phase structure and composition of the coatings were characterized and analyzed by means of scanning electron microscopy(SEM), X-ray diffractometer(XRD) and energy dispersive spectrometer(EDS) analysis, and the wettability and corrosion resistance of the coatings were studied by using optical contact angle measuring instrument and electrochemical workstation. The results show that compared with the Ni-Co-Si_(3)N_(4) and Ni-Co-Al_(2)O_(3) coatings, the surface grain of the Ni-Co-Si_(3)N_(4)-Al_(2)O_(3) nano-composite coatings is refined, uniform and dense, and the average grain size is the smallest, which is 19.20 nm. The surface static water contact angle of the Ni-Co-Si_(3)N_(4)-Al_(2)O_(3) nano-composite coatings is 131.4°, and shows the best hydrophobicity. Electrochemical tests show that, under the simulated soil solution conditions, the self-corrosion current density and corrosion rate of the Ni-Co-Si_(3)N_(4)-Al_(2)O_(3) nano-composite coatings are 1.30 μA·cm^(-2) and 0.016 mm·a^(-1), respectively, the charge transfer resistance is 214.91 kΩ·cm^(-2), exhibiting the best corrosion resistance.