| Metal corrosion causes great economic loss and damage to society. With the progress of industry and technology, it is important to research materials corrosion. Inhibitor is a chemical species or admixture, which exists in the medium and can prevent from corrosion or retard corrosion. It is an effect method to use inhibitor to prevent metals and its alloys corrosion in environmental medium.316L stainless steel is an austenitic stainless steel consisting molybdenum, and its corrosion resistance was improved much than normal stainless steel. It is the most widely applied material in the chemical industry, metallurgical and medical and so on. The corrosion of Metal materials were researched by many researcher, however, few people focused on the corrosion of 316L stainless steel. Corrosion data is not enough and is inaccurate. Therefore, it is essential to study the corrosion of 316L stainless steel to supply new data.Soak method and Tafel polarization curve method were used to test the corrosion resisting property of 316L stainless steel under different condition in this paper, and the mechanism was discussed. Alternating current impedance method was used to examine process of corrosion and results. The following was concluded considering the experimental results:(1)The effect of different corrosive mediums on corrosion rate is: sulphuric acid>phosphoric acid>soda.(2)Upon increasing temperature, the corrosion rate accelerates when sulphuric acid is used.(3) Corrosion rate increases with the increasement of sulphuric acid concentration. However, the corrosion rate decreases due to passivation occurs when the concentration of sulphuric acid is above 90%.(4)The dosage of corrosion inhibition is related to concentration of corrosive medium. In the 20% concentration of sulphuric acid solution, the dosage of thiourea is 0.04% and hexamethyl tetramine is 0.2%, respectively. In the 40% concentration of sulphuric acid solution, the dosage of thiourea is 0.07% and hexamethyl tetramine is0.15%, respectively. And In the 60% concentration of sulphuric acid solution, the dosage of thiourea is 0.1%, while hexamethyl tetramine is not suitable for use. The effect of sodium molybdate as inhibitor is not obvious in sulphhuic acid solution.(5) In the dense phosphoric acid solution, the dosage of thiourea is 0.2% and hexamethyl tetramine is 0.07%, respectively.(6)The corrosion mechanism under different conditions is discussed.(7)The process of corrosion was researched with the electrochemistry impedance method.The corrosion data of 316L stainless steel were obtained under different conditions and supplied new corrosion data, which supplies reference for intelligent use and preserved for corrosion of 316L stainless steel. |
