Friction and Wear Characteristics of Iron Oxide Coating

Abstract

Friction and wear characteristics of Fe_2O_3,Fe_3O_4,reduced iron and α-FeOOH were experimentally examined in the absence of lubricant. Each iron oxide showed a specific friction and wear motion. Fe_2O_3 showed the lowest friction coefficient and generated no frictional noise under the entirely test condition. Fe_3O_4 had an optimal friction speed and load to minimize the friction coefficient. The frictional noise, unlike Fe_2O_3,was generated at every test condition. While the friction coefficient of reduced iron was a little larger than that of Fe_2O_3 at lower friction speed and load. As the friction speed and load increased, the friction coefficient gradually approached that of Fe_2O_3 due to the formation of Fe_2O_3 film along the sliding surface. α-FeOOH showed no lubricating ability.