Abstract: The interfacial characteristics of the Ti coated diamonds and uncoated diamonds was investigated.The interfaces were brazed by high-frequency induction with two kinds of NiCr alloys on the same conditions.The grains brazed by high-frequency induction were immerged into the mixed acids for several hours and then rinsed with acetone.The interfacial characteristics of the grains were studied with scanning electron microscope,energy dispersion spectrometer and X-ray diffraction.The results show that the composition and the shape of carbides of the brazed diamond grains are different when different solders were used to braze diamonds with or without Ti coatings.The Cr carbides of brazed Ti coated diamond grains are normally and compactly formed,whereas,the Cr carbides on the surface of brazed uncoated diamond are tangentially and loosely formed.The abrasive experiment indicates that the bond strengths between the carbide and the diamonds are also different with different carbides.