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This paper outlines the history and background of the NLGI (formerly known as the National Lubricating Grease Institute) lubricating grease specifications, GC-LB classification of Automotive Service Greases as well as details on the development of new requirements for their High-Performance Multiuse (HPM) grease certification program. The performance of commercial lubricating grease formulations through NLGI's Certification Mark using the GC-LB Classification system and the recently introduced HPM grease certification program will be discussed. These certification programs have provided an internationally recognized specification for lubricating grease and automotive manufacturers, users and consumers since 1989. Although originally conceived as a specification for greases for the re-lubrication of automotive chassis and wheel bearings, GC-LB is today recognized as a mark of quality for a variety of different applications.

Silicone fluids are known to have high Viscosity Indices (VI), and high Oxidation Onset Temperatures (OOT). Silicone VI and OOT characteristics make these fluids appealing for use as lubricants in high temperature applications, and where lubricant longevity is desired. Despite thermal and oxidative benefits, silicones lubricants have a reputation as being poor lubricants in metal-to-metal applications, and are typically only selected for use in plastic applications. Most industrial knowledge about silicone lubricants is based on characteristics of PolyDiMethyl Siloxanes (PDMS), in which case, lubricity limitations do exists. However, there are other silicone based lubricating fluid technologies, that have been commercially available for decades, that far exceed known lubricity performance of PDMS, and in some ways can rival traditional synthetic hydrocarbon.

When designing and employing lubricants, film thickness modeling techniques must be used as part of an overall design approach to insure mating components, in relative motion have proper lubricating films to separate surface asperities. Improper asperity separation will lead to increased friction and wear, and overall reduce system reliability, serviceability, and efficiency. Many of the tools to model tribofilms used today are rooted in empirical studies completed with hydrocarbon based fluids as the lubricating medium. Generally, these modeling techniques have also been applied to non-hydrocarbon based lubricants, and this may not be an accurate method to model such fluids. As demands for improved lubricant performance continue to rise, so too does the need for improved tribofilms modeling techniques. This paper will discuss a modeling techniques developed, in which, silicone based polymer molecular structures are designed with tribological film performance in mind.