Studies on the Effect of Graphite Content on Hardness and Electrical Resistivity of Silver-Graphite Composites

Abstract:

Silver-Graphite composites are attractive materials for electro-mechanical devices to provide noise free rotation between mating surfaces with minimum contact voltage drop. In the present study, the composite was processed through Powder Metallurgy (P/M) route considering that the constituent elements have divergent physical properties without any metallurgical bond between them. The developed composites were evaluated for hardness, electrical resistivity, contact voltage and density. This paper presents a correlation between hardness and electrical resistivity against volume fraction of graphite added, through linear regression which has clearly indicated that the said properties of the composites are highly dependent on the volume fraction of graphite. The hardness and electrical resistivity of the composites were found to obey the relations given below (i) Log H=1.522 + 1.667 Log (1-fg), (ii) 32.36 Log (ρ0/ρ) =1 + 83.74 Log (1-fg), where H is hardness of composites, ρ0 is electrical resistivity of pure silver, ρ is electrical resistivity of composites and fg is the volume fraction of graphite.

• Periodical: Materials Science Forum (Volume 710)
• Pages: 326-331
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.710.326
• Online since: January 2012
• Authors: G.P. Khanra, S. Girikumar, De Gangadhar, Deepak K. Mishra, T.T. Saravanan, S. Dineshraj, S.C. Sharma
• Keywords: Brush Blocks, Electro-Mechanical Devices, Green Compaction, Sintering

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