烧结碳气氛对CVD涂层刀片基体脱β层厚度的影响

Effect of Sintering Carbon Atmosphere on the Thickness of Cubic Carbide Free Layer of CVD Coated Blade Substrate

为了研究烧结气氛对硬质合金脱β层厚度的影响,本研究以WC、Co、Ti(C,N)、(Ti,W)C和(Ta,Nb)C粉末为原料,通过脱氮气氛烧结制备了WC-(Ti,W)C-Ti(C,N)-(Ta,Nb)C-Co梯度硬质合金,并分析了Ti(C,N)含量和烧结碳气氛对合金微观组织与性能的影响规律。结果表明,添加Ti(C,N)将促进立方相向合金内部扩散,钴往外的扩散驱动力增强,在合金表面形成岛状或层状覆钴现象。烧结气氛主要是通过合金表面的碳含量来影响液相和立方相的迁移来影响脱β层的形成,随烧结炉碳气氛升高,脱β层厚度减少,添加0.9%Ti(C,N)制备的梯度硬质合金在低、中、高3种碳浓度气氛中脱β层厚度分别为20.2μm、10.7μm、0μm,因此,碳浓度气氛是影响脱β层厚度的一个重要因素。

In order to study the influence of sintering atmosphere on the thickness of cubic carbide free layer of cemented carbide,the gradient hardness of WC-(Ti,W)C-Ti(C,N)-(Ta,Nb)C was prepared by sintering in denitrogenation atmosphere with WC,Co,Ti(C,N)-(Ti,Nb)C as raw materials.The results show that the addition of Ti(C,N)will promote the diffusion of cubic phase into the alloy,and the driving force of cobalt diffusion will be enhanced,forming island or layered cobalt coating on the alloy surface.Sintering atmosphere mainly affects the carbon content on the alloy surface,the migration of liquid phase and cubic phase,and the formation of debetabelting layer.With the increase of carbon atmosphere in sintering furnace,the thickness of debetabelting layer decreases.The thickness of debetabelting layer of gradient cemented carbide prepared by adding 0.9%Ti(C,N)is 20.2μm,10.7μm and 0μm in low,medium and high carbon concentration atmospheres,respectively.Carbon concentration atmosphere is an important factor affecting the thickness of debetabelting layer.