Ti对Zn-Al合金薄膜耐腐蚀性能的影响

EFFECT OF Ti ON THE ANTI-CORROSION PROPERTY OF Zn-Al ALLOY FILMS

应用组合材料芯片技术,以离子束溅射法在低碳钢基片上制备了不同Ti掺杂量的Zn-Al-Ti薄膜(Al和Zn质量分数分别为55%和45%)样品阵列.沉积得到的多层薄膜经低温扩散和高温晶化形成合金薄膜.以电化学方法测定合金薄膜在浓度(质量分数)为3.5%的中性NaCl水溶液中的耐蚀性能,并进一步研究了优选出的组分的耐蚀性.结果表明,Ti的适量掺杂可使合金薄膜的耐蚀性能明显提高.其中,Ti的质量分数在6%左右时耐蚀性能最佳.采用XRD及SEM对6%Ti的合金薄膜的相结构和表面形貌进行了表征,并与未掺杂Ti的薄膜进行了比较.此外,分析了Zn-Al-6%Ti合金薄膜的腐蚀机理,为进一步优化薄膜体系提供了依据.

Zinc coatings have been widely used to provide corrosion protection for metal materials because they act as barriers and sacrificial anodes to prevent their protected substrates from becoming rust.However,it is seldom satisfactory for zinc coatings to meet the more demanding anti-corrosion needs in severer atmosphere.The increased requirements for enhancing anti-corrosion properties have led to the industrial production of zinc alloy coatings.A range of Zn-Al coatings were thus developed as replacements for zinc coatings.Further researches on Zn-Al coatings indicated that the anti-corrosion properties of the binary system can be improved by doping other elements.Besides,metal titanium could exhibit outstanding anti-corrosion properties under a wide variety of environments.Therefore, Zn-Al-Ti thin films or coatings are strongly supposed to be the promising materials for improving anti-corrosion properties.Using the combinatorial material chip technology,Zn-Al-Ti thin films with different Ti contents（where the mass fraction of Al to Zn are 55%and 45%,respectively） were synthesized on the low-carbon substrate by an ion beam sputtering method.The as-deposited multilayer films were transformed into alloy films after a two-step annealing：diffusion at lower temperature and crystallization at higher temperature.The anti-corrosion behavior of the alloy films in 3.5%（mass fraction） neutral NaCl aqueous solution was determined by the electrochemical methods.Further experiments were conducted to investigate the corrosion properties of the optimized composition.The results indicate that the doping of Ti obviously improves the anti-corrosion properties of the Zn-Al films,where the optimal content of Ti doping is around 6%（mass fraction）.The structure and morphology of the optimal alloy film were characterized using XRD and SEM,respectively.Besides, the anti-corrosion mechanism of the ternary Zn-Al-Ti alloy films was analyzed,which provides some useful results for the further research on the alloy film systems.