Stability of friction fade-out at polymer-like carbon films slid by ZrO2 pins under alcohol-vapored hydrogen gas environment. (November 2016)

• Record Type: Journal Article
• Authors: Nosaka, Masataka; Kusaba, Ryota; Morisaki, Yushi; Kawaguchi, Masahiro; Kato, Takahisa
• Is Part Of: Proceedings of the Institution of Mechanical Engineers. Volume 230:Number 11(2016:Nov.)
• Page Start: 1389
• Page End: 1397
• Publication Date: 2016-11
• Subjects: Polymer-like carbon -- diamond-like carbon -- zirconia -- H2 gas environment -- alcohol vapor -- catalytic reaction -- friction fade-out -- superlubricity; Tribology -- Periodicals; 621.89
• DOI: 10.1177/1350650116636797
• Languages: English
• ISSNs: 1350-6501

Abstract

Friction tests using ZrO2 (Y-PSZ: yttria partially stabilized zirconia) pin slid against polymer-like carbon film of bilayer and multilayer structures under H2 gas environment are conducted. It will be shown that friction coefficients of the level of 0.0001 (friction fade-out) is stably realized by adding alcohol vapors to H2 gas during run-in stage, then by stepping up the load from 19.8 N to 63.7 N after run-in stage. Four kinds of vapors of alcohol aqueous solutions are tested using bilayer samples, and ethanol-vapored H2 gas shows the longest friction fade-out duration. Polymer-like carbon/diamond-like carbon multilayer sample shows long-life friction fade-out of 4 h, and it will be shown that the friction trace of 4 h reflects wear process of the first layer of polymer-like carbon and the second layer of diamond-like carbon. ZrO2 surface is observed by an optical microscope and scanning electron microscopy and measured by surface profiler after friction fade-out test, and it is shown that flat contact area at the central region has many blisters and crimps, and is surrounded by peripheral bumps. It is also shown that the sliding marks are seen only at the top of crimps at the central region. Raman measurements indicate that short-chain carbons are predominant at blisters and ring carbons of small clusters are predominant at bumps. With these observations friction fade-out mechanism is discussed.