Papers by Keyword: Sodium Tungstate

Abstract: The present study emphasizes the effect of addition of sodium citrate (C₆H₅Na₃O₇.2H₂O) and sodium tungstate (Na₂WO₄.2H₂O) to a silicate based electrolyte system on the corrosion behavior of PEO treated ZM21 magnesium alloy. The phase composition of the as-developed coating was evaluated by X-ray diffraction (XRD) analysis, while its surface morphology, thickness and elemental distribution were observed using scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). Potentiodynamic polarization tests were done in 3.5 wt% NaCl solution to analyze the corrosion behavior of the ceramic coatings in simulated marine environment. The results of XRD showed that the phase composition of all coatings comprised of Mg₂SiO₄ and MgO irrespective of the additive used. In addition to Mg, Si and O, the presence of W, C in EDS spectrum indicated that these elements were incorporated into the coating from the electrolyte system containing tungstate and citrate. The corrosion test results revealed that the PEO coatings obtained in tungstate containing electrolyte solution showed higher corrosion resistance than those formed in citrate containing electrolyte solution.

Abstract: The corrosion weight loss method and polarization curve measurement were conducted to study the effects of the complex inhibitor of sodium tungstate and urotropine on the corrosion of 304 stainless steel in the 3.5% NaCl solution. The results indicated that the complex inhibitor has good synergistic inhibitory effect for stainless steel in the NaCl solution. Combining sodium tungstate and urotrpine at a total concentration of 500 mg/L, when the mass ratio of sodium tungstate to urotrpine was 7:3, the inhibitory effect was optimum. In addition, the probable inhibitory mechanism was analyzed.

Abstract: Crystalline WO3 nanorods of less than 100 nm in diameter have been successfully synthesized at 240 °C for 72.0 h with pH=1.5 in the system of strong acid with sodium tungstate and potassium sulphate by the hydrothernal method. The morphologies and structures of WO3 rods have been characterized and analyzed by XRD, SEM, TEM and SAED. SEM confirmed that the slenderness ratio of WO3 rods was enlarged with the increase of t the pH value and the reaction time. SAED analysis showed that the crystal morphology of the synthesiezed WO3 nanorods was crystallin. UV-VIS results showed that the absorbent power of UV light for WO3 nanorods enhanced with the increase of their slenderness ratio.