Formation of Lubricating Films at Elevated Temperatures from the Gas Phase

摘要

Conventional liquid lubricants, when subjected to temperatures of 250 deg C and above for extended time in an air atmosphere, degrade rapidly to make large amounts of solid sludge and deposits. Based on boundary lubrication of bearings, these same lubricants, when subjected to 250 deg C to the melting point of the bearing metal, produce in the micro- to milli-second residence time in the bearing contact enough 'friction polymer' to result in good lubrication. The report describes the use of these conventional liquid lubricants delivered in a homogeneous vapor phase where the carrier gas is nitrogen, air or mixtures of these two gases. The lubricants studied include alkyl and aryl phosphate esters, organic acid esters, polyphenyl ethers, and mineral oil.