烧结工艺对脱β层厚度及性能的影响

改变硬质合金烧结工艺控制的几个关键因素,通过测量合金的理化性能,利用扫描电镜分析合金的内部结构,研究了烧结气氛(真空,N_2)、烧结温度、烧结压力对硬质合金梯度结构和机械性能的影响。结果表明,对于含氮硬质合金的梯度烧结,适时引入一定量的氮气可抑制合金中含氮物质的早期分解,可用氮压来控制梯度增长速率,烧结气氛中氮气压力适宜控制在100～200 mbar;随着烧结温度的提高,合金的致密度和脱β层梯度厚度增加明显,合金抗弯强度增加;随着烧结压力的增大,合金脱β层梯度厚度变薄。

Effect of Sintering Process on Thickness and Properties of Cobalt-rich Layer

Through changing a few key factors of sintering process,the effect of sintering atmosphere（vacuum,N_2）, temperature,pressure on the gradient structure and mechanical properties of cemented carbide was researched by physical and chemical properties measurement and inner structure analysis with scanning electron microscope（SEM）.The experimental results show that,for the sintering of nitrogen-containing cemented carbide,blowing in a certain amount of nitrogen can inhibit the decomposition of nitrides in the cemented carbide.The growth rate of the gradient layer can be controlled by changing the nitrogen pressure.Suitable sintering atmosphere of nitrogen pressure should be controlled in 100～200 mbar.With the increase of sintering temperature,the density and cobalt-rich layer thickness of the cemented carbide obviously increase,and the flexural strength increases.With the increase of sintering pressure,the cobalt-rich layer thickness is thinner.