Premium
Tribological properties and lubrication mechanisms of a Ag–Mo composite
Author(s) -
Zhang Tiantian,
Huang Chuanbing,
Lan Hao,
Du Lingzhong,
Zhang Weigang
Publication year - 2016
Publication title -
lubrication science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.632
H-Index - 36
eISSN - 1557-6833
pISSN - 0954-0075
DOI - 10.1002/ls.1306
Subject(s) - composite number , lubrication , materials science , tribology , sintering , microstructure , powder metallurgy , molybdenum , metallurgy , molar ratio , composite material , phase (matter) , chemistry , catalysis , organic chemistry
A composite material containing silver and molybdenum metals was fabricated by powder metallurgy method with a Ag/Mo molar ratio of 2 : 1 and the sintering temperature is 700°C. Tribological properties, especially the solid lubrication behaviours during oxidation of the composite in air, were considered from room temperature to 600°C. Phase composition, microstructure and thermal behaviour of the composite were analysed before and after tests to investigate the lubrication mechanisms. The friction coefficients of the composite are ~0.7 below 400°C but decrease sharply to ~0.18 above 500°C. Characterisations of this composite indicate that several silver molybdates (Ag 2 MoO 4 , Ag 2 Mo 2 O 7 and Ag 2 Mo 4 O 13 ) formed from oxidation of Ag–Mo composite at high temperatures benefit lubrication effects and lead to the decrease of friction coefficients. Formation mechanism of these silver molybdates during oxidation and wear was therefore studied, and a model based on solid reaction processes in the Ag–Mo–O 2 system was promoted. Copyright © 2015 John Wiley & Sons, Ltd.