Select And Study On Corrosion Mechanics Of Corrosion Resistant Materials In Sulfer-Bearing Solution

As the phenomenon of sulfur corrosion in the oil refining, the influence of corrosion on normal materials were discussed emphasisly in different concentration of sulfur-bearing solutions at different temperatures, the author investigated the corrosion tendencies, corrosion rates, surface corrosion morphologies of 45# carbon steel, stainless steel, chromium coating and Ni-P alloy coatings, disclosed the characters and mechanics of corrosion resistant materials in this study. The corrosion behaviors of above materials in sulfur-bearing solution were studied by potentiostatic polarization method, corrosion rates of materials were measured in different concentration of Na2S solutions at different temperatures by gravimetric method, organize morphologies of stainless steel welding joint were observed by using microscopic test method, surface corrosion morphologies of 45# carbon steel and stainless steel were investigated using field emission scanning electronic microscope, ingredients and structure of electroless plating Ni-P alloy coatings were investigated using X-ray photoelectron spectrometer and X-ray diffraction instrument in this study. Experimental results indicate that the corrosion rates of 45# carbon steel in Na2S solution are increase firstly, and then reduce with the increasing of Na2S mass percent. The pitting corrosion of carbon steel is severe in lower mass percent Na2S solution, corrosion is mainly confirm corrosion at high Na2S mass percent. The corrosion of austenitic stainless steel in sulfur-bearing solution is the corrosion system which is controlled by the activation polarization at lower temperatures, the surface of stainless steel appears passivation at high temperatures. The corrosion resistance of 304 stainless steel manual metal-arc welding joint of A102 welding electrode was prior to that of A307 welding electrode at the same welding technology, the welding joint of A307 welding electrode exists larger foreign materials, and appears intercrystalline corrosion seriously. When chromium coating were used in Na2S solution between 20℃and 80℃, the 1.0% must be avoided. The perfect mass percent of Na2S is 1.4% or so. The amorphous Ni-P plating of P11.98mass% is deposited with cellular structure on the surface at the experimental technology, the corrosion rates of coating is within the 10-3g/m2·h order at 80℃, therefore, Ni-P alloy coatings is a kind of corrosion-hindering material.