Effect of Reaction Temperature on Pickling of 430 Stainless Steel
stainless steel is used as raw material and pickling in HCl-based electrolytes is adopted, and the effect of pickling temperature on removal behavior of the oxide layer on stainless steel is systematically studied, study found that the oxide layer of stainless steel after heat treatment in the lab is composed of Fe2O3 and Cr2O3, at different temperatures, with the increasing of duration, corrosion potential of stainless steel after heat treatment shows fall followed by rise, and corrosion potential of stainless steel in 60°C is obvious higher than in 50 °C; with temperature increasing, the weight loss of stainless steel after pickling increase with large range, and the weight loss of the oxide layer of stainless steel increases as the duration increases.
Passivation of Stainless Steels in Hydrochloric Acid
High alloyed stainless steels (Fe20Cr20Ni, Fe20Cr20Ni6Mo, and Fe20Cr20Ni6Mo0.2N) were polarized in 0.1 M HCl + 0.4 M NaCl solution for 10 min and 2 h between {minus}75 and 800 mV vs. saturated calomel electrode (SCE). The composition of the passive films was analyzed by angle-resolved X-ray photoelectron spectroscopy, and showed that oxide particles are formed during the initial stage of the passivation process. It is suggested that they are formed by deprotonation of hydroxide. For prolonged exposure, a uniform oxide film is developed under the hydroxide layer. The composition of the film is strongly dependent on the potential. Molybdenum decreases while Cr, Fe, and Ni increase with the potential. The content of Cr in the hydroxide layer decreases with the potential. {beta}-MoCl{sub 2} is identified in the film on the Mo-containing steels. Chloride is present in both the oxide and hydroxide layers. The film forced at {minus}75 mV(SCE) on the Mo-free alloy contains over 50% more Cl{sup {minus}} compared to the film formed on Mo-containing steels. It is suggested that one of the beneficial effects of Mo in stainless steels is that it forms soluble oxochloro complexes, which thereby lower the amount of Cl{sup {minus}} in the film and makesmore » the steel more resistant to pitting.« less
Characterization of W Films on Si and SiO2/Si Substrates by X-Ray Diffraction, AFM and Blister Test Adhesion Measurements
Contrary to most classical adhesion test, the blister test provides quantitative adhesion energy measurements. We demonstrate its application to 1 03BCm thick W films in tensile stress state deposited by xenon DC magnetron sputtering on PECVD/Si(100) substrates. The W films surface morphology, structure and residual stress were also characterized by atomic force microscopy, X-ray diffraction and substrate curvature measurements as function of the deposition pressure. Films characteristics are compared with those of W films deposited directly