Xiaoxiao Zhang , Shaomin Zhang , Cheng Yang , Ze Sun , Jiawei Ding
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引用次数: 0
Abstract
The electrochemical corrosion performance of WC-Co hard alloy was studied under pressure/pressureless sintering and conditions with/without graphene oxide added. Three electrochemical testing methods were used to evaluate the corrosion behavior: open circuit potential, electrochemical impedance spectroscopy, and dynamic potential polarization. The corrosion resistance of the alloy was compared using three parameters of corrosion potential, corrosion current density, and total impedance. The corrosion mechanism was studied by observing the surface morphology of corroded alloy using scanning electron microscopy and analyzing the surface corrosion products using X-ray photoelectron spectroscopy. The results showed that pseudo-passivation phenomenon appeared in the potentiodynamic polarization curve of the hard alloy in the sodium hydroxide solution. The corrosion behavior was mainly controlled by anodic dissolution, with the dissolution of WC phase being greater than that of Co phase. The corrosion resistant properties of the pressure sintered cemented carbide are higher than that of the pressure-less sintered cemented carbide respectively in NaOH solution, mainly because pressure increases the grain size and decreases the grain boundaries of cemented carbide, which can be regarded as the dislocation wall between grains and normally attacked by the serious corrosion preferentially.
研究了 WC-Co 硬质合金在加压/无压烧结以及添加/不添加氧化石墨烯条件下的电化学腐蚀性能。采用了三种电化学测试方法来评估腐蚀行为：开路电位、电化学阻抗光谱和动态电位极化。使用腐蚀电位、腐蚀电流密度和总阻抗三个参数比较了合金的耐腐蚀性。通过扫描电子显微镜观察腐蚀合金的表面形貌，并利用 X 射线光电子能谱分析表面腐蚀产物，研究了腐蚀机理。结果表明，硬质合金在氢氧化钠溶液中的电位极化曲线出现了伪钝化现象。腐蚀行为主要受阳极溶解控制，WC 相的溶解度大于 Co 相。在 NaOH 溶液中，加压烧结硬质合金的耐腐蚀性能分别高于无压烧结硬质合金，这主要是因为加压使硬质合金的晶粒尺寸增大，晶界减小，晶界可视为晶粒间的位错壁，通常优先受到严重腐蚀的侵蚀。
期刊介绍：
The International Journal of Refractory Metals and Hard Materials (IJRMHM) publishes original research articles concerned with all aspects of refractory metals and hard materials. Refractory metals are defined as metals with melting points higher than 1800 °C. These are tungsten, molybdenum, chromium, tantalum, niobium, hafnium, and rhenium, as well as many compounds and alloys based thereupon. Hard materials that are included in the scope of this journal are defined as materials with hardness values higher than 1000 kg/mm2, primarily intended for applications as manufacturing tools or wear resistant components in mechanical systems. Thus they encompass carbides, nitrides and borides of metals, and related compounds. A special focus of this journal is put on the family of hardmetals, which is also known as cemented tungsten carbide, and cermets which are based on titanium carbide and carbonitrides with or without a metal binder. Ceramics and superhard materials including diamond and cubic boron nitride may also be accepted provided the subject material is presented as hard materials as defined above.
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