Powder Metallurgical Silver-Graphite Electrical Contact Materials

The research work deals with processing and evaluation of silver-graphite electrical contact materials containing 1 wt.%, 3 wt.% and 5 wt.% graphite. The study involves the synthesis of silver-graphite composite powders by various powder processing routes like conventional method of mixing/blending of the constituent powder particles, and the alternative synthesis routes based on the nanotechnology principles viz. high- energy milling, colloidal synthesis and electroless deposition. The raw materials and the synthesized powders were characterized using techniques such as particle size analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM), electron spectroscopy for chemical analysis (ESCA), X-ray fluorescence spectroscopy (XRF) and transmission electron microscopy (TEM), etc. The density, hardness, electrical conductivity measurements and the microstructural examination were done for consolidated bulk solid compacts of above powder processing routes. The representative AgC contacts produced by high- energy milling route were subjected to the electrical performance evaluation.