对硝基苯甲酸钠对碳钢的缓蚀行为研究

A STUDY ON INHIBITIVE ACTION OF SODIUM p NITROBENZOATE FOR CORROSION OF CARBON STEEL

用失重法和电化学方法研究了对硝基苯甲酸钠对碳钢（２０号钢）腐蚀和氧化皮－碳钢电偶腐蚀的缓蚀行为。在５０°Ｃ的５．０×１０－３ｍｏｌ／ｌＮａＣｌ溶液中，对硝基苯甲酸钠在浓度≤５．５×１０－３ｍｏｌ／ｌ时促进碳钢腐蚀，浓度在１．０×１０－２－１．５×１０－２ｍｏｌ／ｌ范围时缓蚀率达９６％，浓度高于１．５×１０－２ｍｏｌ／ｌ时缓蚀率下降。极化曲线表明，对硝基苯甲酸钠对碳钢的阴阳极过程均有抑制作用，对阳极过程的抑制更强烈，在适当浓度时可使碳钢钝化。浓度为１．０×１０－２ｍｏｌ／ｌ的对硝基苯甲酸钠对氧化皮－电偶腐蚀的缓蚀率达９８％。

The inhibitive effect of sodium p nitrobenzoate (SpNB) from the corrosion of carbon steel #20 on surfaces and caused by scale substrate galvanic couple in 5.0 mmol/l aqueous NaCl solution at 50°C is studied by weight loss and electrochemical methods.It is shown that the corrosion is promoted by SpNB of concentration ≤5.0 mmol/l but inhibited by SpNB of concentration ≥7.5 mmol/l and a high inhibition rate of 96% is observed at concentration range 10-15 mmol/l.The polarized curves obtained indicate that SpNB inhibits both the anodic and cathodic processes on the carbon steel and the former is inhibited in more extent.The carbon steel can be passivated by adequate amount of SpNB.SpNB in concentration of 10 mmol/l inhibits the corrosion of carbon steel caused by the scale substrate galvanic couple by a rate of 98%.