Dissertation
Dissertation > Industrial Technology > Metallurgy and Metal Craft > Metallurgy and Heat Treatment > Metal corrosion protection,metal surface treatment > Various types of metal corrosion

Corrosion Behavior of Bulk Nanocrystalline 304 Stainless Steel

Author SunZuo
Tutor ZhangYan;WangShengGang
School Shenyang University of Technology
Course Applied Chemistry
Keywords Nanocrystalline materials Pitting High-temperature oxidation Hot corrosion Electrochemical Corrosion Behavior
CLC TG172
Type Master's thesis
Year 2010
Downloads 130
Quotes 2
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Stainless steel is widely used because of its superior corrosion resistance in all areas of modern society. However, the in many corrosive environmental media, the corrosion of stainless steel is still often happens, especially prone to harm local corrosion. In-depth study of stainless steel corrosion mechanism is of great significance for guiding the development of ultra-high corrosion resistance of stainless steel materials and surface modification technologies. Nanomaterials because of their unique physical, chemical and mechanical properties, caused widespread concern of researchers in various fields. The corrosion behavior of nanomaterials has also become a research focus in the field of Corrosion Science. This article was prepared by using the deep rolling technology bulk nanocrystalline materials, and selection of ordinary cast alloy as a comparative experiment samples to study the corrosion behavior of nanocrystalline materials in different corrosive environmental media. The study showed that of 304 stainless steel pitting behavior: nano nanocrystalline 304 stainless steel corrosion the surface of the oxide film of Fe, Cr, Ni element binding energy higher than that of ordinary cast 304 stainless steel, this oxide film is complete, stable coverage the surface of the base body, while the activity of the Cl-ions of the oxide film is significantly reduced, resulting in slow-down in the speed of dissolution of the film, to improve the resistance of nanocrystalline 304 stainless Cl-ion erosion performance. Nanocrystalline 304 stainless steel SS orbital electron lower weight, therefore during the corrosion process in the chemical reaction rate is significantly reduced, resulting in the of Nanocrystalline 304 stainless steel of the chemical stability is improved. Studies have shown that high-temperature oxidation behavior of 304 stainless steel: nano nanocrystalline 304 stainless steel surface can form a protective Cr2O3 oxide film, due to the small grain size of the matrix, the lower critical concentration leads to the formation of continuous Cr203 oxide film, while producing the positive effect of the grain boundaries, thereby improving the high temperature oxidation resistance of the material. Studies have shown that the hot corrosion behavior of 304 stainless steel: the nano, the increase in the number of grain boundaries grain refinement of nanocrystalline 304 stainless steel, so that the the Cr element to an increase in the surface diffusion channel, the substrate surface to the rapid formation of a protective Cr2O3 oxide The film, and the oxide film formed without cracking and shedding phenomenon, thereby improving the corrosion of the heat-resistant material. Studies have shown that the electrochemical corrosion behavior of 304 stainless steel: Nano, the resistance of nanocrystalline 304 stainless steel SO42-ions and performance enhancements, aqueous corrosion resistance to Cl-ions to the surface of a large number of grain boundary Cr element in the rapid spread of surface The rapid diffusion channel, so that its surface is formed a passivation film having a higher stability, thereby improving the corrosion resistance of the material. Studies have shown that the electrochemical corrosion behavior of industrial pure iron: nano, the resistance to hydrochloric acid the bulk nanocrystalline industrial pure iron corrosion than coarse-grained industrial pure iron significantly improved, uniform due to surface of nanocrystalline industrial Iron and texture such that the rolling surface has a surface energy lower than the average surface energy of the coarse grain surface of industrial pure iron, reducing the corrosion of the formation of micro-batteries, thereby improving the bulk nanocrystalline industrial pure iron in the hydrochloric acid solution the corrosion resistance.

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