Study On High-temperature Electrochemical Corrosion Of FV520B Stainless Steel In Bromine Acetic Acid Solution

Compressor is the critical component in Purified Terephthalic Acid(PTA)production system,the high-temperature corrosion often cause the compressor to premature failure in service.Therefore,the blade material needs good corrosion resistance ?The current evaluation method is the conventional corrosion weight-loss method,which is need long time and bigger error.So the development of a new rapid evaluation method is particularly important and urgent.In this paper,the high temperature electrochemical corrosion of FV520 B martensitic hardened stainless steel was investigated in bromoacetic acid solution.The corrosion behavior of materials at high temperature by electrochemical method was studied,and the effects of bromine acetic acid,bromine ion and temperature were also future investigated.Then we summarizes the best corrosion resistance range and provide a reference for the material service.The main contents are as follows:(1)The corrosion behavior of FV520 B blade in typical environment was evaluated by potentiodynamic polarization curves,it showed that corrosion potential and corrosion current increased with extending temperature,leading to uniform corrosion rate increase.While pitting potential is increase after the first drop with increasing temperature.Corrosion rate rise along with pitting potential decline when bromide ion concentration increase(2)The paper describes the effect of acetic acid,temperature and bromide ions on the electrochemical behavior of blade under high temperature.It shows that the acetic acid promote uniform corrosion rate of the blade.It does not have significantly influence on pitting corrosion behavior of blade which is mainly affected by temperature and bromide ion concentration.(3)The factors affecting stability of oxide film was clarified and the best service referenc e range was summed up based on observing and characterizing of surface oxide film morphol ogy.It showed that the growth of oxide film was promoted with rising temperature,and bromi ne ions,hydrogen ions accelerated oxidation film dissolve.The best service range of materials is 170?-180? and 50-200 PPM.