CORROSIVE WEAR AS A FAILURE MODE IN LUBRICATED GEAR CONTACTS

Corrosive wear due to oxygen and/or moisture in the air is shown to be a major form of gear failure. Using a Micro-Ryder Gear Tester, it is shown that with diester-based lubricants, damage is worse in air than in a dry inert atmosphere at low loads; at higher loads, damage is more severe in the inert atmosphere. For a highly-refined mineral oil, better performance is shown in an inert atmosphere than in either a room-air or wet-air atmosphere. Based on microscopic examination of damaged gears and surface finish measurements, it is concluded that tooth damage in air is due to corrosive wear while in inert atmosphere, scuffing occurs. Both corrosive wear and scuffing can be controlled by additive treatment. A mechanism is discussed which suggests that continued oxide formation from corrosive wear serves to prevent scuffing under high loads. © 1969.