Analysis on interfacial products of the joint of cubic boron nitride brazed to CuNiSnTi filler metal

The microstructure and formation mechanism of the products in the interface of the joint of c-BN brazed to CuNiSnTi filler metal were investigated by scanning electron microscope(SEM), energy dispersion spectrometer(EDS), as well as micro X-ray diffraction(XRD). Also, the growth process and diffusion activation energy of the interfacial reaction products were deeply studied with a kinetics theory. The results showed that the CuNiSnTi filler metal exhibited a good wettability on c-BN in the brazing. And the reaction between filler metal and c-BN occurred, therefore the reliable connection between c-BN andJP2steel substrate was realized. The new phase of Ti-N and Ti-B compounds were found in the interface between filler metal and c-BN. Then the formed structure of the interface was in the form of filler/TiN/TiB/TiB2/c-BN. The growth process of reaction layer depends mainly on the inter-diffusion among the atoms and chemical reaction generated at the interface in the brazing temperature of 1153-1193 K for 5-20 min following a parabolic rule.