Papers by Keyword: Alkaline Corrosion

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Authors: Xiaohui Tu, Jun Quan Liu, Wei Li, Jun Yi Su
Abstract: Abstract. Hot concentrated alkaline corrosion and wearing corrosion environment exists in alumina metallurgical industry. Iron and steel materials with outstanding alkaline corrosion resistance are strongly demanded for their fabrication equipments. In this paper, corrosion resistance in static hot concentrated alkaline solution of several kinds of martensite chromium cast iron and steel was studied through polarization curves, potential-time curves, weight loss in the corrosion, and corrosive morphology analysis. Experimental results indicated that corrosion processes can be divided into three stages: dissolving of passivating films, exposed surface corrosion, and corrosion beneath the corroded product. Protection effect of the passivating films was transitory, and the corrosion rate during the exposed surface corrosion reached the maximum. Corrosion of the testing materials was composed of active dissolving corrosion of the metal matrix and caustic embrittlement cracking of the matrix, as well as grain boundary corrosion for the cast iron. Dissolving corrosion of the metal matrix was the main cause that induced the weight loss, while severe caustic embrittlement cracking of the metal matrix was disadvantageous. With an increase of the chromium content in the cast iron or steel, active dissolving corrosion of the metal matrix increased. However, the tendency of caustic embrittlement cracking decreased.
Authors: Xin Yan Yuan, Heng Gen Shen, Zhen Hua Wang, Wei Li Hou
Abstract: In order to reveal the influence of acidic gas SO2 and CaO etc alkali substances which are contained in industrial furnaces smoke to the strength of PSA fiber, tests are made in different acid and alkali conditions, and the changes of its surface morphology were observed by scanning electron microscope (SEM). The results show that: PSA has better acid corrosion resistance than alkali corrosion resistance. Its acid corrosion resistance is similar to the domestic aramid. PSA is better than Nomex in the concentration of 5% H2SO4. Its alkali corrosion resistance is worse than domestic aramid. The retention rate of breaking strength drop to 60.80% and 69.52% respectively after treated in the concentration of 5% H2SO4 for 48 hours and in the concentration of 5% NaOH for 4 hours. The elongation rate decline to 68.14% and 40.22% respectively, and the elongation rate fell to 68.14% and 40.22% respectively. Therefore, the PSA must be dealt against corrosion when used in strong acid or alkali environment.
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