The Experimental Study On Diamond Abrasive Grain Layer Process Prepared By Electrode Sparking Deposition

The surface consolidation of electrode sparking deposition (ESD) is such a process that the electrode material is deposited to the substrate surface through the spark discharge of pulse power to achieve a metallurgy combination. This process can effectively repair surface defects of work-piece. Simple and easy to operate, the device of this process has developed rapidly and fruitful results have been yielded in this field. However, little domestic research has been done on abrasive grain layer of ESD device. The experimental study on the process of diamond abrasive grain layer by ESD device is conducted in this paper by drawing on previous studies and referring to the Research and Development and Application Demonstration of theRemanufacturing Technology and Device of Grinding Wheel with Metallic Substrate, a national scientific and technological project. Research content was as follows:(1) The line of compacted powder electrode manufacturing process was studied. The electrode structure of copper layer, transition layer and discharge was designed, which improved conductive properties and clamping performance of the electrode.(2) The electrode formula and electrode compressing and sintering process were studied. The influence of the content of Cu, Co, and diamond on electrode performance was explored. The final electrode formula and the scheme on electrode compressing and sintering process were obtained.(3) The experiment on the process of abrasive grain layer of ESD device was done by means of electrode spark shaping machine in the working liquid of special kerosene on the 45# steel substrate.The results showed that the ability of electrode deposition had much to do with the electrode polarity and copper content. When positive polarity was used, the deposition effect was rather poor.When the copper content reached more than 24%, the deposition effect of electrode materials was still badly even in negative processing. The study on the influence of the discharge parameters on the deposition thickness of the abrasive layer was conducted and the quality transitional mechanism during the process of ESD was probed into. It was found that post-processing could improve the deposition thickness of the abrasive layer as the deposition thickness of the abrasive layer had a tendency to saturate due to thermal stress. The results from the research on the bonding characteristics of the abrasive layer indicated that the abrasive layer and the substrate were metallurgical combination with high intensity. Topography analysis, composition analysis and structural analysis on the abrasive layer were done by means of scanning electron microscopy (SEM), X-ray diffraction (XRD) equipment, the pores and cracks in the abrasive layer were studied, and the causes and preventive measures of crack extension were explored. The research on the characteristics of diamond grain deposition showed that during deposition the diamond was not oxidized and maintained a certain sharpness and intensity. Hardness distribution on the surface and cross section of the abrasive layer was measured, which exhibited that its hardness was obviously higher than that of the matrix and that the bonder had a strong strength on diamond grains.In this study, diamond abrasive layer was prepared on 45# steel substrate via the experiment on the process of ESD, which played an essential role in the research on the repair and remanufacturing of metal matrix diamond wheel and had certain significance.