Reasearch On The Application And Operating Mechanism Of Rare Earth In Diamond Tools

As a kind of special composite, the properties of matrix to diamond particles impregnated on that of tools is the most key factor. This thesis investigated effects of compounds of rare earth, La-Ni alloy powder, mixed rare earth and Ni alloy powder, and Ce02, on the matrix properties of granite saw blade, and Al-Ce alloy powder on the matrix for cutting glass.Through thermodynamic and kinetic analysis of the rare earth elements' action in metal matrix/diamond composite interface reaction, it was found that La, Ce can play an active role in the interface reaction under the sintering condition.This paper is focused on a series of relatively complex issues such as the adding type, adding form and adding amounts of the rare earth material. At the same time, the matrix composites in this research have been optimized. The result showed that proper amount of rare earth alloy powder notably increases the abrasive resistance of diamond/metal composite, while addition of CeO2 trended to decrease the abrasive resistance of the composite. When the rare earth alloy powder content is 0.8~1.0%, the bending strength and bonding property of composite get maximum. The flexural strength of the composites with rare earth-Ni alloy powder increases by 32% over that of the composites free of rare earth elements, the hardness increases by 13%, and the porosity decreases to 0.52%.SEM, EDS and X-Ray were used to investigate the fracture section, the microstructure change of matrix material, the distribution of elements and the interface of matrix-diamond. The results showed that the addition of the rare earth alloy powder can refine and disperse oxide particles. Through energy spectrum analysis, it was found that the rare earth congregates to Ti and the interface between metal matrix and diamonds. The active La and Ce in alloy powder can reduce the oxide film on Ti particles, increase the reactivity of Ti, and promote the reaction between Ti and diamond. The results showed that the combination of rare earth element La and transition element Ti is advantageous to the bonding state between diamond particles and matrix. So it can improve the materials properties.The research improved that the functions of the rare earth are catalysis activation, dispersion strengthening and purification of the metal matrix/diamond composite interface. Finally theintegral properties of the matrix materials are increased.By cutting test, the cutting speed and longevity of the diamond saw blades with rare earth-Ni alloy are increased compared to that of the saw blades free of rare earth elements. The addition of CeO2 can decrease the viscidity of matrix. It is suitable for cutting flexible stone materials. The addition of Al-Ce powder to the saw blades matrix for cutting glass, crystal has reached a promising result and has applied to production. This research has proved a reference to improve the saw blade's performance.