ABSTRACT The main goal of the present work is to study the influence of the microstructure on the corrosion behavior of cemented carbides WC-Co in two corrosive media. Corrosion kinetics were determined by immersion tests while the electrochemical evolution of the Surface was analyzed using impedance testing. Damage tolerance to corrosion was evaluated by assessing fracture strength on specimens previously subjected to corrosion. Results pointed out that for both grades the corrosion rate was higher in seawater, being more significant for the grade with a medium grain size. The corrosion phenomenon that took place in both media was caused by the oxidation reaction of cobalt. In seawater, the polarization resistance decreased for both grades whereas in mine water increased, due to the formation of a layer of corrosion products, which slowed down the cobalt dissolution process in Surface. In both media, a greater strength loss of the ultrafine grades was evidenced.

中文翻译：

---

显微组织对WC-Co硬质合金腐蚀损伤的影响

摘要 目前工作的主要目标是研究微观结构对硬质合金 WC-Co 在两种腐蚀介质中的腐蚀行为的影响。腐蚀动力学通过浸没试验确定，而表面的电化学演变使用阻抗试验进行分析。通过评估先前经受腐蚀的试样的断裂强度来评估腐蚀的损伤耐受性。结果表明，这两个等级的腐蚀速率在海水中都较高，对于中等晶粒尺寸的等级更为显着。两种介质中发生的腐蚀现象都是由钴的氧化反应引起的。在海水中，两个等级的极化电阻都降低，而在矿井水中，由于腐蚀产物层的形成，极化电阻增加，这减缓了 Surface 中钴的溶解过程。在这两种介质中，都证明了超细等级的强度损失更大。