酸性盐溶液中复合缓蚀剂对304不锈钢缓蚀作用的研究

Corrosion inhibition of composite inhibitor on stainless steel in acid salt solution

为了研究不同缓蚀剂及复合型缓蚀剂对304不锈钢在酸性(pH=1)3.5%氯化钠溶液中的最佳缓蚀效果、最佳复配效果和最佳复配比例,采用失重法、电化学方法、表面形貌观察法、表面接触角和表面张力等表征方法对咪唑、硫脲、铬酸钾这三种物质的缓蚀效果及复配效果进行了研究.结果表明:失重法和表面形貌观察法均显示出三种物质都有一定的缓蚀效果,其缓蚀效率的大小关系为:硫脲>铬酸钾>咪唑,最佳缓蚀时间为24 h;通过极化曲线Tafel外推法、电化学阻抗谱法和表面形貌观察法等均可得出最佳复配效果为硫脲与铬酸钾复配;将100 ppm的硫脲5 mL和100 ppm的铬酸钾5 mL进行复配时(复配比为1∶1)通过表面接触角和表面张力的方法可得最小接触角为46.5°,最小表面张力71.9 mN/m,故最佳复配比为1∶1,即在硫脲与铬酸钾配比为1∶1且时间为24 h时,这种复合型缓蚀剂对304不锈钢的缓蚀效果最佳.

In order to study the best corrosion inhibition effect,the best compounding effect and the best compounding ratio of 304 stainless steel in acidic（pH = 1） 3. 5% sodium chloride solution with different corrosion inhibitors and compound corrosion inhibitors,the corrosion inhibition effect and compounding effect of three kinds of substances such as imidazole,thiourea and potassium chromate were studied by the method of electrochemistry,electrochemical observation,surface morphology observation,surface contact angle and surface tension. The results showed all three kinds of materials had certain corrosion inhibition effect by using the weight loss method and the surface morphology observation method. The inhibition efficiency of the three kinds of materials was as follows： thiourea 〉potassium chromate 〉imidazole,and the best corrosion inhibition time was 24 h. The best compounding effect for thiourea and potassium chromate could be obtained by the polarization curve of Tafel extrapolation method,electrochemical impedance spectroscopy and surface morphology observation. It had the minimum contact angle of 46. 5° and the minimum surface tension of71. 9 m N/m at the compounding ratio of 1∶ 1 which was 5 mL100 ppm of thiourea and 5 mL100 ppm potassium chromate complex by the surface contact angle and the surface tension method,so the best compound ratio was1∶ 1. When the ratio of thiourea and potassium chromate was 1 ∶ 1 and the time was 24 h,it had the best corrosion inhibition effect on 304 stainless steel.