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分别采用浸泡和电化学实验方法对Ni-W-Cu-P镀层在常温和高温20%H2SO4溶液中的耐蚀性进行了研究,用SEM,EDS及XRD对镀层的沉积机制、成分结构进行了分析.结果表明:球形Ni-W-Cu-P核心合并生长形成条状组织;共沉积W和Cu可显著提高Ni-W-Cu-P非晶的热稳定性;400℃热处理非晶的耐蚀性优于镀态非晶和500℃热处理纳米晶的;延长腐蚀时间,非晶和纳米晶镀层的腐蚀速率和腐蚀电流密度增大,阻抗则下降;Ni-W-Cu-P非晶和纳米晶镀层的腐蚀机制分别是选择性腐蚀和点腐蚀.
The corrosion resistance of Ni-W-Cu-P coating in 20% H2SO4 solution at room temperature and high temperature was studied by immersion and electrochemical experiments respectively. The deposition mechanism and composition of the coating were studied by SEM, EDS and XRD The results show that the spherical Ni-W-Cu-P core grows to form strip-like microstructure. Co-deposition of W and Cu can significantly increase the thermal stability of Ni-W-Cu-P amorphous. The results show that the corrosion rate and the corrosion current density of amorphous and nanocrystalline coatings increase and the impedance decreases when the etching time is extended by prolonging the etching time. The Ni-W-Cu-P amorphous and The corrosion mechanism of nanocrystalline coatings are selective corrosion and pitting corrosion respectively.