WC-Co硬质合金稀土-硼共渗的高温动态相分析

Dynamic XRD Phase Analysis of Rare Earth-Boronization for WC-Co Cemented Carbides

用高温X射线衍射装置对以B4C为供硼剂、以Y2 O3 为催渗剂的WC 2 0Co硬质合金渗硼表面进行了从室温到 130 0℃连续升温渗硼过程的XRD动态物相分析 ,探讨了稀土 硼共渗机制。结果表明 ,在真空烧结升温期间 ,从WC Co压坯表面B4C分解出来的活性硼原子除在压坯表面上形成硼化物外 ,所形成的高浓度活性硼原子还向压坯内钴中扩散形成三元含硼相W2 Co2 1 B6化合物。同单独渗硼相比 ,钇在稀土 硼共渗过程中有拓宽渗硼温度范围。

The dynamic XRD phase analysis for the coated surface with B 4C and Y 2O 3 of WC 20Co cemented carbides sample was carried out during vacuum heating from room temperature to 1300 ℃ by high temperature X ray diffraction apparatus. The boronization mechanism was explored on the basis of above results. The results show that the high concentration active boron atoms released from the boron supply agent B 4C located on the blank surface diffuse into the Co phase in blank leading to forming boron bearing W 2Co 21 B 6 compound besides forming boron bearing compounds on the blank surface. By contrast with boronization without rare earth metal, yttrium in boronization agent broadens the boronization temperature range during vacuum sintering, catalyses the de carbonised decomposition of B 4C and promote diffusion of active boron atoms into WC Co blank.