中文摘要：

通过对WC-6%Co（质量分数）超细硬质合金烧结后的表面形貌进行扫描电镜（SEM）和能谱（EDS）分析,分析和讨论造成合金表面麻点、呈灰黑色和出现黑斑的原因,得出合金碳含量和烧结气氛对合金表面贫钴和吸附杂质、富钴的影响机制,及该实验条件下造成合金表面形貌及成分差异的原因。合金碳含量比烧结气氛碳浓度低时,合金表面极易出现贫钴现象,同时表面会吸附烧结气氛中夹杂的C,O,Ca,S杂质元素;反之,会出现合金表面富钴现象,合金表面不会吸附O,Ca,S杂质元素。合金碳含量与烧结气氛碳浓度高低变化,而使合金表面既有富钴区、又有贫钴区时,合金表面有麻点或呈灰黑色;合金渗碳时,合金表面易有黑斑出现;合金表面富钴且一致时,合金具有正常金属光泽。

英文摘要：

The surfaces of sintered WC-6% Co （ mass fraction） uhrafine cemented carbide samples were tested by means of scanning electron microscope （SEM） and energy dispersed spectroscopy （EDS）, and the reasons which caused pitting, grayish black and dark spots on the surfaces were analyzed and discussed. The mechanism of poor cobah, adsorption of impurities and rich cobalt on the alloys＇ surface caused by carbon content and sintering atmosphere was obtained. The reason for the differences of morphology and composition on the alloy surface in the experimental conditions was also analyzed. When the carbon content was lower than the carbon concentration in sintering atmosphere, poor cobalt phenomenon on the surface was easy to appear, and C, O, Ca and S impurities in the sintering atmosphere were adsorbed. On the contrary, there would be rich cobalt phenomenon, and O, Ca, S impurity elements were not adsorbed. The changes of carbon content and carbon concentration in sintering atmosphere would cause Co-rich and Co-poor areas on the surface, thus leading to pitting, grayish black or dark spots on carburizing alloy surface. The alloy would have normal metallic luster when cobalt was rich and consistent on the surface.