Industrial Titanium And Oocr25ni22mo2, Stainless Steel Erosion Corrosion And Passivation Properties Discussed

In present paper, the methods of weight loss and electrochemistry (including polarization resistance, polarization curve, scratching electrode and AC impedance, etc.) were employed to study the erosion-corrosion behaviors and repassivative mechanism of commercially pure titanium and 00Cr25Ni22Mo2 (abbreviated as 25Cr-22Ni-2Mo in follow) stainless steel in lmol/L H2SO4 solution by changing rotating speed and test temperature with the aid of the self-designed rotating apparatus and scratching electrode apparatus.The experimental results of weight loss showed that the corrosion rate of Ti and 25Cr-22Ni-2Mo in lmol/L H2SO4 solution enhanced with increasing the rotating speed and raising the temperature, and more obviously at high rotating speed (>800rpm) and at high temperature ( 85, 95). At lower temperature, Ti has better corrosion-resistant ability than 25Cr-22Ni-2Mo; but at 95, the situation is reverse. Increasing in rotating speed enhanced the value of Rp-1 of two materials, the trend tending to less degree at high rotating speed ( >800rpm). The value of Rp-1 firstly enhanced with raising temperature, then follow down, this may be associated with the changing of the films.The polarization curves showed that the two materials were in passivative state between +150mV and +800mV(vs. S. C.E.), and the passivation current density increased gradually by raising the temperature.The scratching electrode test showed that the repassivation ability of the two materials firstly enhanced with increasing the temperature, then down; at lower than 88, the repassivation abilityof Ti was better than that of 25Cr-22Ni-2Mo, and at higher than 88, it was reverse, that is accordance with the weight loss results.Single capacitance semicircles on EIS of Ti and 25Cr-22Ni-2Mo in lmol/L H,SO4 solution were observed under static or dynamic condition 'and different temperature. The value of Rp was reduced with raising the temperature, but it did not change the characteristics on EIS of two materials, showing that erosive effect and temperature did not change two materials' process of corrosion and mechanism of solution. In present test conditions, temperature is an important effect to the corrosion resistance of the film of the two materials.