The electrochemical behavior of ultrafine WC/μ-WC-Co alloy with different grain sizes of WC particles was investigated in 1M HCl and 1M NaOH solutions using potentiodynamic polarization and surface analytical techniques. Good linear grain size dependence existed for the corrosion current density (I_corr). Alloys with smaller WC exhibited better corrosion resistance. Addition of μ-size WC particles can weaken the corrosion resistance of ultrafine WC/μ-WC-Co cemented carbide. The corrosion mechanism is discussed based on the SEM and EDS analysis. The predominant dissolution of the Co particles as the binder phase in HCl solution as well as WC matrix remained at the tangent surface. The benefits of Co(OH)₂ protective film can only be utilized in alkaline solution.

中文翻译：

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μ尺寸WC对超细WC / WC-Co硬质合金腐蚀行为的影响

使用电位动力学极化和表面分析技术，研究了具有不同晶粒尺寸的WC颗粒的超细WC /μ-WC-Co合金在1M HCl和1M NaOH溶液中的电化学行为。对于腐蚀电流密度（I _corr），存在良好的线性晶粒尺寸依赖性。WC较小的合金具有更好的耐腐蚀性。添加μ尺寸的WC颗粒会削弱超细WC /μ-WC-Co硬质合金的耐腐蚀性。基于SEM和EDS分析讨论了腐蚀机理。Co颗粒作为粘合剂相在HCl溶液以及WC基质中的主要溶解保留在切线表面。Co（OH）₂保护膜的优点只能在碱性溶液中使用。