## 3 Results  
The COF of friction during the ball-on-disk loss of lubrication experiments had a similar pattern for all of the experiments. Figure 2 shows the COF during an experiment using the baseline DoD-PRF-85734 oil, but it is representative of all the experiments. It can be seen in the figure that the COF was affected by a number of events occurring during the experiments. The first 10 min consisted of the COF slowly approaching a constant value during the run-in period. When the lubricant was cut, at time equals zero in Figure 2, the COF slowly rises until a scuffing event, as marked by the magenta arrows. At the point of scuffing, the friction rises sharply. The time to scuffing was taken as the time difference between when the oil supply is turned off to the point of scuffing, and the mean is shown for all lubricants in Figure 3 with error calculated with 95% confidence. The time to scuffing initiation was higher for all the blends with the additional additives than the baseline oil, which had a time to scuffing of 60.1 s. The time to scuffing initiation was increased by 13% for DoD-PRF-85734 + 0.02 wt% NG to 68.3 s, 66% for DoD-PRF-85734 + 1 wt% IL to 99.84 s, and 103% for DoD-PRF-85734 + 1 wt% IL + 0.02 wt% NG to 122.1 s. The increase in time to scuffing onset for the lubricant with both additives was more than the sum of the increases from the blends with a single additive. Figure 2: Coefficient of friction during ball-on-disk, loss-of-lubrication experiments. (**a**) Entire experiment, (**b**) Zoom in within the dotted. In addition to observing the time to onset of scuffing of the steel specimens, the COF with the lubricant blends was extracted at key points. The COF during the ball-on-disk, loss-of-lubrication experiment was taken at the two points of interest shown in Figure 2, immediately before the lubricant supply was cut and immediately before scuffing. The mean values for the multiple runs of each lubricant blends are shown in Figure 4. The COF was similar for the baseline oil and the two blends with IL additive, around 0.026, before lubricant was cut and 0.039-0.040 immediately before scuffing. Only the DoD-PRF-85734 + 0.02 wt% NG blend differed in that it had a lower COF both before lubricant was cut (0.022) and before scuffing (0.034). An ANOVA analysis gives a \(p\)-value of 0.003 for the COF before lubricant is cut and \(p\) value of 0.104 for the COF before scuffing. A low \(p\)-values indicates a low probability of sampling error producing a difference between the groups as large as those observed here. The scuffing load experiments allowed for the measurement of COF as load is increased and a determination of the load at which scuffing occurs in an EHD-lubricated contact. The COF measured during the scuffing load experiments is shown in Figure 5. For all the lubricant blends, the COF decreases with time as the specimen is run in. There are small increases in COF with each step increase in load, but the overall trend appears to be downward as the specimen is progressively run in. The scuffing load for the baseline oil was 513 N. The scuffing load for DoD-PRF-85734 + 1 wt% IL and DoD-PRF-85734 + 0.02 wt% NG exceeded the maximum load of 620 N for this experiment. The DoD-PRF-85734 + 1 wt% IL + 0.02 wt% NG exhibited a scuffing of 165 N, which is less than for the baseline oil. The COF for the blend with only NG additive follows closely with the COF for the baseline oil. The COF during the experiment was higher for the two blends with IL (about 0.045 at 100 N) than the two blends without (about 0.03 at 100 N) over the full range of loads, however a more rapid decrease in COF was seen over time for the blend with IL and NG tha  
Figure 3: Average time to initiation of scuffing after shutting off oil supply in ball-on-disk, loss-of-lubrication experiments. Error with 95% confidence interval. Figure 4: Coefficient of friction (COF) after running in and just before initiation of scuffing in high speed elastohydrodynamic contact. Error with 95% confidence interval.