Improved additives for multiply alkylated cyclopentane-based lubricants

Abstract

Multiply alkylated cyclopentanes (MACs) are replacing heritage (mineral oil-based) spacecraft lubricants because of their excellent performance and low volatility. While MACs have acquired an increasingly prominent role, soluble additives with similarly low volatility are lacking. In this study, the performance of specially designed candidate high-molecular-weight/low-volatility phosphate additives was compared with the performance of conventional phosphate and lead naphthenate additives currently used in space. The candidate additives were equivalent or superior to the currently used additives in both conventional (atmospheric) and vacuum wear tests. Volatility studies revealed superior candidate additive performance compared with currently used additives. In addition, surface chemical analysis of the wear surfaces provided a better understanding of the anti-wear protective films formed by these additives. Copyright © 2008 John Wiley & Sons, Ltd.