稀土强化金刚石-硬质合金复合凿岩柱齿的试验研究

采用添加镍，磷的低温活化烧结工艺，分别用不同含量的稀土化合物LaNi5和CeO2作为添加剂进行了试验，研究了其对硬质合金，金刚石-硬质合金复合材料及由此构成的金刚石-硬质合金复合凿岩柱齿性能的影响，结果表明；适量的LaNi5和CeO2可显著提高硬质合金及金刚石复合材料的抗弯强度，但对硬质合金硬度的影响不大；适量的LaNi5可使金刚石复合材料的耐磨性有较大幅度的提高，而CeO2的加入则有降低金刚石复合材料耐磨性的趋势，落锤冲击实验表明；添加稀土元素的金刚石-硬质合金复合凿岩柱齿具有较好的抗冲击韧性，能够满足潜孔锤钻进的要求，稀土元素的作用机理主要是强化晶界，消除杂质，细化晶粒以及弥散强化作用。

Effects of Rare Earth on Properties of Diamond-tipped Tungsten Carbide Insert

This study investigated effects of compounds of rare earth, LaNi 5 and CeO 2, on properties of cobalt-cemented tungsten carbide, diamond/carbide composite and diamond-tipped tungsten carbide insert for rock drilling under the active, low temperature sintering process which achieved by adding nickel and phosphorus into the mixed powders. The results show that proper amount of LaNi 5 and CeO 2 could remarkably increase the strength of cemented tungsten carbide and diamond/carbide composite, whilst the hardness of cemented tungsten carbide had a little increase. Proper amount of LaNi 5 notably increased the abrasive resistance of diamond/carbide composite, while addition of CeO 2 trended to decrease the abrasive resistance of the composite. Hammer test of diamond-tipped tungsten carbide inserts shows that their impact resistance toughness increased after proper amount of rare earth compound was added so that they can meet the demands of down-hole-hammer drilling. The functional mechanisms of the rare earth compounds are due to strengthening crystal boundary, eliminating impurity, fining crystal particle and dispersion strengthening.