活性元素Ti在CBN与钎料结合界面的特征

Characteristics of Active Element Ti at the Interface of CBN and Filler Alloy

通过扫描电镜、能谱仪、X射线衍射仪研究了Ag-Cu-Ti钎料中的活性元素Ti在钎料与立方氮化硼(CBN)磨粒高温钎焊结合界面的扩散现象,并运用动力学分析对界面反应层的生长过程及反应激活能进行了探讨。结果表明:钎焊过程中,钎料中的活性元素Ti明显向磨粒侧扩散偏聚并发生化学反应,实现了磨粒与基体材料的牢固结合;钎焊CBN磨粒表面生成的TiB2和TiN化合物形貌接近平衡状态下生长的理想形貌;界面反应层在钎焊温度1153K～1193K,保温时间5min～20min之间依据抛物线生长法则所得扩散激活能值表明其生长过程主要受新生TiN影响。

The characteristics were investigated by scanning electron microscope （SEM）, energy dispersion spectrometer （EDS）, as well as X-ray diffraction （XRD） for the active element Ti of Ag-Cu-Ti filler alloy during brazing in the interface of filler and CBN abrasive grain. Also, the growth mechanism and diffusion activation energy of the interracial reaction layer were deeply studied with a kinetics theory. It is found that the element Ti concentrates to the CBN grains and reacts with them, and makes the abrasive grain strongly join with the steel substrate. The morphologies of TiN and TiB2 compounds formed on the brazed CBN grain are similar to the ideal morphologies in the equilibrium condition. The growth process of reaction layer depends mainly on the newly-formed TiN in the brazing temperature of 1153 K-1193 K for 5 min-20 min according to a parabolic rule.