Oxidation Characteristics of Lubricating Oils at High Temperatures

Lubricating Oil Oxidation and Stabilisation

“…Many factors, which include refining conditions, viscosity index (VI), sulphur content, clay treatment, catalysis by metals and hydrocarbon struc ture, were all investigated in the 1940s and led to the development of relationships between mineral oil composition and oxidisability [7][8][9][10][11][12][13]. Solvent extraction removes aromatic components and improves the VI and the colour of oils and reduces the tendency to form sludge.…”

“…The catalytic effects of solid and soluble lead have been studied by various workers [7,11,13,92,96,97] and it is generally recognized that solid lead and copper are much more readily solubilized than solid iron and oil oxidation is due primarily to homogeneous catalysis by the oil-soluble metal complexes, formed by corrosion, rather than heterogeneous catalytic effects on the surface of the metals.…”

“…Diamond et al studied the oxidation of small volumes (1.5-3 ml) of mineral oils in the range 220-275°C, and found the rate of oxidation de pended on the sample size even within this small range [13]. The catalytic activities of Pb, Cu and Fe varied markedly under these conditions and depended on nature of the catalyst, solid or oil-soluble, and concentration.…”

Polyphenyl Ethers as High-Temperature Radiation-Resistant Lubricants.

“…from 482°to 500°F. and would undoubtedly be higher at higher temperatures (6). As a convenient approximation, the simple Arrhenius equation can be applied-i.e., log t is taken as linear in 1/T-over small temperature intervals.…”

Formation of lubricating films at elevated temperatures from the gas phase

“…Studies of lubrication chemistry over the temperature range covered by bulk systems, elastohydrodynamic bearings and boundary lubrication systems show that oxidation reactions modified by metal catalytic systems predominate [10][11][12][13][14][15][16]. An extension of these reactions to higher temperatures results in excessive sludge and deposits.…”