WC-Al_(2)O_(3)复合材料在不同浓度NaCl溶液中的腐蚀行为

Corrosion Behaviorof WC-Al_(2)O_(3)Composite in NaCl Solution with Different Concentrations

通过真空热压烧结法制备了WC-Al_(2)O_(3)复合材料。采用电化学腐蚀法研究了WC-Al_(2)O_(3)复合材料在不同浓度NaCl溶液中的腐蚀行为,主要测量了开路电位、极化曲线和阻抗谱,并通过SEM和XPS对试样的腐蚀表面进行表征。结果表明,WC-Al_(2)O_(3)复合材料在NaCl溶液中的腐蚀机制为WC相的氧化和Al_(2)O_(3)相的溶解。随着NaCl溶液浓度的增加,腐蚀电流密度由19.2μA/cm^(2)减小至7.5μA/cm^(2),总阻抗由17870Ω·cm^(2)增大至21534Ω·cm^(2),WC-Al_(2)O_(3)复合材料的耐腐蚀性能逐渐提高。当NaCl溶液浓度较高时,溶液中溶解氧含量的降低成为控制电化学腐蚀的主要因素。较低的溶解氧含量抑制了阴极电化学反应过程,进而抑制了整体电化学腐蚀速率。

WC-Al_(2)O_(3)composite was prepared by vacuum hot-pressing sintering method.The corrosion behavior of the WC-Al_(2)O_(3)composite in NaCl solution with different concentrations was studied by electrochemical corrosion method,the open circuit potential,polarization curve and impedance spectrum were mainly mea-sured,and the corrosion surface of the sample was characterized by SEM and XPS.The results show that the corrosion mechanism of the WC-Al_(2)O_(3)composite in NaCl solution is the oxidation of WC phase and the dissolution of Al_(2)O_(3)phase.With the increase of NaCl solution concentration,the corrosion current density decreases from 19.2μA/cm^(2)to 7.5μA/cm^(2),while the total impedance increases from 178702·cm^(2)to 215342·cm^(2),gradually improving the corrosion resistance of WC-Al_(2)O_(3).When the NaCl solution concentration is high,the decrease of dissolved oxygen content in the solution becomes the main factor to control the electrochemical corrosion.The low dissolved oxygen content inhibits the electrochemical reaction process of the cathode,thereby inhibiting the overall electrochemical corrosion rate.