Influences of Trace Water in a Hydrogen Environment on the Tribological Properties of Pure Iron

Abstract

The authors have clarified that trace impurities such as water and oxygen inevitably contained in a hydrogen environment influence friction and wear of metallic materials substantially and even often govern them. In this study, an experimental technique was devised to enable sliding tests in a hydrogen environment which contains controlled concentration of water and virtually no oxygen as impurities. By comparing data of Fe sliding tests between this study and our previous studies, the influences of water and oxygen were understood separately. Water without oxygen as impurity in a hydrogen environment decreased wear of pure Fe while oxygen in additional to water increased the wear. Sliding of pure Fe consumed water when a hydrogen environment contained only water while it produced water and consumed oxygen when the environment contained both water and oxygen. The number of water molecules consumed by sliding in a hydrogen environment with water more than 5,000 ppb and without oxygen was larger than the estimated number of nascent Fe atoms by sliding. This suggests that multi-layer adsorption of water molecules decreased the wear of pure Fe.

Analysis on the Mechanism of Humidity to Influence the Very Early Stage of Sliding under Different Load

“…However, in many articles about friction and wear experiments, the relative humidity of the environment is seldom controlled [1]. Previous researchers found that friction force and wear in sliding can be influenced even by extremely low level as several ppm concentrations of water [2][3][4][5]. The presence of adsorbed water due to the atmospheric humidity on the surface of a material can improve or deteriorate the tribological performances [6,7].…”

A fiber optic sensor with a metal organic framework as a sensing material for trace levels of water in industrial gases

“…Trace water in purified gases can generate problems at use point such as ghost peaks in gas chromatography, and defect in semiconductor products like loss of light emitting efficiency in LEDs [15]. The effect of few ppmv of trace water in hydrogen environment on the tribological effects has also been detailed [16]. Quality control analysis of gases used in an industry is important at each stage, including production, transfer, and use of the gas.…”

A phosphorescent Ir(iii) complex with formamide for the luminescence determination of low-level water content in organic solvents

“…[1][2][3][4][5][6][7][8][9][10][11][12] Usually, Karl Fischer titration and gas chromatography are used for the determination of water contents. [1][2][3][4][5][6][7][8][9][10][11][12] Usually, Karl Fischer titration and gas chromatography are used for the determination of water contents.…”