TRIBOLOGICAL BEHAVIOR OF ARCING CONTACT MATERIALS BASED ON COPPER INFILTRATED TUNGSTEN COMPOSITES
Tungsten copper composites with 70±3 wt.% W, maximum 1.5 wt.% Ni, and balance Cu were achieved as disks (diameter × height of 50×6 mm) by copper infiltration process of tungsten skeletons. Elemental analysis was assessed by WDXRF spectroscopy. Hydrostatic density was evaluated in ethanol. Vickers hardness and Young’s modulus were determined in ambient air by instrumented indentation technique and Oliver&Pharr computation method. Tribological behavior was investigated under 30 N up to 400 m sliding distance and naphthenic mineral oil lubricant with a standard tribometer of ball-on-disk type. The results yielded highly dense materials with relative density over 96%, Vickers hardness (HVIT) of 244…323, Young’s modulus (EIT) of 156…185 GPa, mean coefficient of friction of 0.11…0.22 and specific wear rate up to 8×10–6 mm3/(Nm). The developed composites with low coefficient of friction and high wear resistance for use as arcing contacts in oil circuit breakers will endow high performance in service.
Keyword(s): tungsten copper composites, coefficient of friction, wear rate, naphthenic mineral oil lubricant.
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