Figure 8 The diameter of steel ball wear scar while the 928 and 50-1-4Ф aviation lubrication oil samples (oxidized for 2 hours) are applied
As expected, the total acid number (TAN, shown in Table 3) of the oxidized 928 and 50-1-4Ф aviation lubrication oils were increasing with higher oxidation temperature, which coincident with the anti-wear testing shown in Figure 8. Both the TAN and diameter of wear scar would be promoted rapidly while the oxidation temperature exceeds 230 oC. The oil quality of the oxidized oil samples is undoubtedly deteriorated in the oxidation reactions. As described before, the color number of the oxidized oil samples might provide a readily method to identify the oil quality through the direct measurement of the color-related-oxidation-products. As shown in Figure 2s, the methods still need improvement to elevate the resolution ratio and measurement range. More sophisticated and effective testing strategies about designment on more effective filtration and thinner oil pipe might be required to realize the above demands.