Characterization of Model Perfluoropolyalkylethers by Miniaturized Thermal Oxidative Techniques—Part I: Modified Oxidation-Corrosion Test

The effect of hard coated metals on the thermo‐oxidative stability of a branched perfluoropolyalkylether lubricant

“…Versions of this test are included in military specifications MIL-PRF-7808 and MIL-PRF-23699 and test method ASTM D 4636. The correlation between a miniaturized OC test and the larger scale ASTM test method was previously completed and reported [2]. Although the detailed apparatus description is not given, a summary is provided here.…”

“…Failures are generally caused by excessive coupon weight change or the appearance of particles in the test fluid. The coupon weight change failure criteria, based on the area of the coupon, have been previously established based on experience [2]. This allows comparison between coupons with different surface areas.…”

“…The problem with using these fluids for high-temperature applications is that they decompose and cause corrosion in the presence of ferrous and non-ferrous metals and alloys [1][2][3][4][5][6][7][8][9]. Fluid decomposition also occurs in tribological environments at relatively low temperatures in boundary lubrication at asperity contacts.…”

“…Aluminium and ferrous alloys are the most studied substrates with respect to PFPAE research [2][3][4][5][6][7][14][15][16][17]. These metals are highly reactive with the PFPAE decomposition products at high temperatures and readily produce aluminium and iron fluorides respectively.…”

A review of the effect of metals on the thermo-oxidative stability of perfluoropolyalkylether lubricants

“…The problem with using PFPAE fluids for various applications is they decompose and cause corrosion in the presence of ferrous and certain non-ferrous metals and alloys either when exposed to high temperatures or in boundary lubrication at relatively low temperatures [1,[8][9][10][11][12][13][14][15]. A two-step fluid decomposition process has been proposed [6,8,15]: conversion of the metal surface to a metal fluoride which functions as a Lewis acid site; and catalytic decomposition of the fluid by interaction with these Lewis acid sites.…”