| 摘要 |
PURPOSE:To obtain a twin WC having a high hardness and improved resistance to plastic deformation and high toughness, by the presence of an iron family metal or a compound thereof in preparing the WC by heating W and C. CONSTITUTION:A mixed powder of W with C is mixed with one or more iron family metals in an amount of 0.05-2.0wt% calculated as the metal. The resultant mixture containing inevitable impurities is then heated in a reducing, neutral or vacuum atmosphere at 1,000-1,800 deg.C to give a twin WC in which two WC's are joined at a crystal face (001). If the amount of the iron family metal of the compound thereof added is lower than the lower limit, the rate of the twin WC formation is low. On the other hand, if the amount exceeds the upper limit, the activation energy for the carbonizing reaction is too great, and the rate of the twin WC formation is reduced with the disappearance of the twin nucleus and the rapid growth of the face other than the crystal face (001). If the heating temperature is lower than the lower limit, the growth rate of the twin WC is low, and the crystal is extremely fine with the low rate of formation. If the temperature is higher than the upper limit, the crystallizing rate of WC is high, and the rate of the twin WC formation is reduced with the disappearance of the twin nucleus, and the too rapid growth of the crystal face (001). |
