Conclusions

It has been demonstrated in a high temperature environment that a continuous uniform film can be formed on a variety of metal surfaces, as well as on a quartz surface. On all of these surfaces the rate of coating increases with increasing temperature over the 500 to 800 C temperature range studied. In all cases, the rate of deposit increased with increasing amounts of TCP vapor in the nitrogen carrier gas delivered to the hot test specimen.

Quartz appeared to supply a noncatalytic solid surface on which the deposit rate was constant with time. Stainless steel provided a catalytic surface on which TCP vapors produced a film at a rapid rate initially. This deposition rate decreased with increasing film thickness indicating a loss of catalytic effect with increasing film thickness. The loss of deposition rate with film thickness is attributed to a loss in the availability of iron at the coating surface to act as a catalyst. Iron has been shown to be an effective catalyst in the promotion of chemical film formation from TCP vapors at high temperatures.

Vapor delivered TCP at 370 C provided the formation of an effective lubricating film for M50 tool steel balls in a four-ball wear tester. The presence of an excess of TCP vapor in the four-ball wear tester tends to cause an increase in wear, due to the trapping of metallic wear debris in the excess lubricating film formed. Over a reasonable range of TCP vapor concentration in nitrogen, this lubricant delivered to a four-ball wear system at 370 C compares favorably with the performance of a state of the art 10W-30 (sf-cd) motor oil run in a four-ball wear tester as a liquid at 75 C.

Based on preliminary CKTTF results, the vapor phase lubrication concept for advanced engines appears to show sufficient potential. Vapor lubricated liners exhibit a running surface similar to well lubricated production parts. Liners with 0.0 mole percent vapor concentration tend to scuff.

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