Lubricant, test parameter, effect

Rather than just assessing the condition of the lubricant at a series of set temperatures, Method 9 attempts to determine the temperatures, for a given test duration, at which the various deterioration parameters reach critical assessment levels , e.g. an increase in TAN of 1.5 mg KOH/g. Further tests are then conducted at even higher fixed temperatures to determine the time, or effective life it takes to reach that same assessment level. The result is an extensive set of data relating these assessment levels with time and temperature. The ultimate goal is to construct an Arrhenius plot showing the relationship between effective life and temperature for each deterioration parameter. 

OIT is a widely used screening parameter for the oxidative stability of polymers, edible oils, and lubricants, which is typically used as a quality control tool to rank the effectiveness of various oxidation inhibitors. It is a kinetic parameter (i.e. dependent on both time and temperature) and not a thermodynamic property. As a parameter dependent on test time and temperature, the OIT value appears to be decreasing with time but in a well-behaved and predictable manner. OIT is either a measure of the amount of antioxidant present in the polymer or the effectiveness of the particular AO used. If the amount of AO in the polymer is known, then OITime or lOTemperature allow monitoring residual AO contents and calculation of the linear rate of AO consumption. A major limitation of DSC-OIT is that if the isothermal test temperature is lowered below the standard 200° C temperature to reveal small differences in AO concentration at low levels, the polymer s exothermic oxidation rate may decrease below the limits of DSC detectability. Lugao et al. [120] have recently introduced a temperature dependent oxidative induction time (TOIT) in order to cope with some limitations of the traditional OIT method. 

For the performance of tribological contacts the important parameters in terms of achieving fuel economy are friction and wear. ZDDP is most commonly used as an anti wear additive plus it often has anti-oxidation properties [1]. The effect of ZDDP on friction performance is often complicated. In the literature, there have been reports where ZDDP formulated lubricants produced higher friction than lubricant formulations without ZDDP [12-16]. Holinski [12] used the Bartel lubrimeter which was designed to test gear oils under boundary conditions. He investigated the effect of boundary layers formed from different additives on friction and wear, and found that when the lubricant is... 

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