WC-Co硬质合金烧结过程渗硼的高温动态相分析

THE HIGH-TEMPERATURE DYNAMIC XRD ANALYSIS OF BORONIZATION DURING VACUAUM-SINTERING FOR WC-Co ALLOY

用 PHIL IPS X’PETRθ- θ测角仪对以 B4 C为供硼剂的 WC- 2 0 Co硬质合金的渗硼表面进行了从室温到 130 0℃真空烧结渗硼过程的 XRD动态物相分析 ,探讨了硬质合金烧结过程的表面渗硼机理。结果表明 ,在真空烧结升温期间 ,WC- Co硬质合金压坯表面上的 B4 C在 85 0℃以上分解出来的活性硼原子除在压坯表面上供形成含硼化合物外 ,所形成的高浓度活性硼原子向压坯内钴相 (γ相 )中扩散溶入 γ相晶格内并形成高钴含量的三元含硼相 W2 Co2 1 B6 化合物 ,WC- Co硬质合金真空烧结过程渗硼的有效温度范围为 85 0～ 10 0 0℃。

The high-temperatare dynamic XRD phase analysis for the coated surface with B 4C of WC-20Co cemented carbides powder blank sample during vacuum-heating it from room-temperature to 1300℃ was done by high-temperature X-ray diffraction apparatus.The results show that,the high concentration of active boron atoms released from the boron-supply agent B 4C located on the surface of alloy blank above 850℃ diffuse into the Co-phase in blank leading to forming the W 2Co 21 B 6 compound except for forming boron-bearing compounds on the blank surface,The effective temperature range is 850～1000℃ for boron-doping during vacuum-sintering WC-Co cemented carbides.