Silicone oils have long been valued for their thermal stability, water repellency and material compatibility. Nevertheless, their use in lubrication has traditionally been limited to selected applications because of comparatively low lubricity and load-carrying capability. As regulatory scrutiny of PFAS substances intensifies and industry seeks alternative technologies, silicone-based lubricants are attracting renewed attention.
Recent formulation developments demonstrate that some historical limitations can be mitigated through optimized thickener systems and modern additive technologies. This article discusses the evolving role of silicone lubricants, presents key findings from tribological investigations and highlights application areas where modern silicone greases can offer a technically viable alternative.
Why Silicone Greases Are Back on the Agenda
Silicone grease technology is attracting renewed interest as lubricant formulators respond to evolving regulatory developments and growing demand for PFAS-independent lubrication solutions. While PFPE- and PTFE-based lubricants continue to represent the benchmark for applications operating under extremely harsh conditions, requiring thermal stability, chemical resistance, broad material compatibility and long service life, many industrial applications operate under demanding, but less extreme, conditions.
Lubricant development is increasingly moving away from “one-to-one replacement thinking.” The focus is instead on identifying where PFPE/PTFE systems remain essential and where alternative chemistries can provide a suitable balance of performance, durability and regulatory acceptance.
Within this context, silicone oil-based greases are receiving renewed attention. Advances in formulation design are allowing them to cover a broader range of industrial applications than in the past. This reflects a more selective approach, where lubricant types are chosen according to the requirements of the application rather than being replaced broadly across product families.
Understanding Silicone’s Strengths and Trade-offs
Silicone oils are well-established synthetic lubricant base fluids characterized by thermal stability, chemical inertness and broad material compatibility. Their silicon-oxygen backbone, compared with the hydrocarbon structure of conventional base oils such as mineral oils, esters, PAOs and PAGs, provides stable viscosity-temperature behavior, high oxidative resistance and reliable performance across a wide operating temperature range.
This property profile makes silicone oils particularly suitable for applications where long-term stability, elastomer compatibility, resistance to moisture and temperature extremes are more important than maximum load-carrying capability. Typical examples include valve and sealing systems, where elastomer compatibility is critical; damping elements, which require stable viscosity across wide temperature ranges; and electrical or food-processing applications, where chemical inertness and water repellency contribute to long service life.
Despite these advantages, silicone oils exhibit inherent tribological limitations. Their low polarity limits adsorption on metallic surfaces and reduces boundary film formation under load.
As a result, silicone lubricants have traditionally been selected for applications where thermal stability and material compatibility outweigh extreme load requirements. Advances in grease formulation are now extending their applicability beyond these traditional boundaries.
Designing Performance Without PTFE
The increasing demand for PFAS-independent lubrication options has accelerated the development of advanced silicone grease formulations.
High-performance silicone greases have long relied on PTFE as both a thickener component and a solid lubricant, particularly in applications involving higher loads where friction and wear control are important.
Current formulation work therefore focuses not only on replacing PTFE, but also on maintaining key performance targets such as friction stability, wear protection and load-carrying capacity through alternative solid lubricants and additive combinations.
Recent laboratory tests indicate that these goals can be achieved for selected formulations. Several PTFE-free silicone grease formulations reached weld loads comparable to PTFE-containing reference systems in four-ball tests, while SRV tests demonstrated stable, low-friction behavior throughout the test duration.
These results indicate that PTFE is not strictly required to achieve comparable tribological performance, provided the formulation is properly balanced. Modern PTFE-free systems can match the load-carrying and friction behavior of PTFE-containing products in numerous applications through a combination of thickener systems, solid lubricants and functional additives.
Design Principles of Silicone Oil-Based Lubrication Systems
The data confirms a consistent pattern across silicone-based grease systems. Performance is not driven by individual raw materials but by the overall formulation. Base oil, thickener, solid lubricants and additives act together as one system and need to be evaluated as such.
In practice, this means that key parameters must be interpreted differently. Base oil viscosity defines the operating range of a lubricant, not its tribological performance. Base fluid chemistry determines the general characteristics of the system, while the final performance is governed by the interaction of multiple formulation components. Similarly, differences between PDMS and phenyl-modified silicones can influence where a product performs best, but they cannot predict performance on their own.
From a product perspective, silicone greases should therefore be treated as systems whose performance depends on formulation balance rather than individual material selection.
Where Silicone Greases Make Sense Today
Modern silicone greases combine the known strengths of silicone chemistry with improved tribological performance, making them suitable for a wider range of applications than in the past.
They provide an additional option for applications where performance requirements and regulatory constraints need to be balanced. This positions them as complementary to established PFPE-based solutions rather than direct replacements.
Rather than being associated with a particular industry, their selection should be driven by the functional requirements of the application. Components operating in the presence of water, moisture or cleaning agents benefit from the inherent water repellency and chemical stability of silicone oils, while assemblies containing elastomers or engineering plastics often require lubricants with broad material compatibility and stable frictional behavior.
In food-related applications and in sealing systems, valves and fluid-handling equipment, lubricants are often exposed to moisture, steam, aggressive cleaning procedures and water-based or polar media. Under these conditions, reliable performance relies on stable consistency, resistance to washout, chemical stability and compatibility with elastomeric materials. Silicone greases can maintain lubrication and sealing performance over extended relubrication intervals, whereas resistance to extreme mechanical loads is often of lesser importance.
A similar situation is seen in the automotive sector, where silicone greases are used across an expanding range of components. Beyond traditional applications in damping and vibration control, they are used in actuators, seat adjustment mechanisms, sunroof guides and charging flap mechanisms that require consistent operating forces and reliable function over extended service intervals.
At the same time, the growing number of electrical connectors, connector seals and actuator assemblies in electrified vehicles has further increased the importance of lubricants offering excellent compatibility with engineering plastics and elastomers. These developments illustrate how the ongoing shift toward electrification and mixed-material designs is creating additional application opportunities for modern silicone grease formulations.
Beyond the automotive sector, similar trends can be observed in industrial equipment, where the increasing use of lightweight and mixed-material assemblies has expanded demand for silicone greases. In these applications, lubricants are required to combine material compatibility with low noise generation, reliable operation over a wide temperature range and long-term durability.
Across these use cases, selection is driven by clearly defined operating conditions, with silicone greases used where their property profile provides a reliable technical fit.
Consequently, modern silicone greases should not be viewed as niche products limited to a few specialized applications. Instead, they represent one option within a broader lubricant portfolio, particularly where moderate mechanical loads coincide with demanding environmental conditions, sensitive materials or extended service-life requirements.
Viable Option
The results highlight a clear shift in silicone grease development from material-based thinking toward formulation-driven performance design. While silicone oils have traditionally been considered less suitable for high-load applications because of their inherent tribological limitations, the results demonstrate that these limitations can be significantly reduced through modern grease formulation strategies.
In the context of increasing regulatory pressure on PFAS-containing technologies, silicone greases represent a technically viable option for selected industrial applications. Their role is not to replace established high-performance lubricants across all applications, but to expand the range of available solutions for application-specific requirements.
As lubricant technologies continue to diversify, the selection of base fluids will increasingly be guided by application-specific requirements rather than established material preferences. Silicone greases illustrate this development well. Rather than being assessed primarily on the basis of their historical limitations, they are increasingly evaluated according to the performance of the complete formulation.
At the same time, growing demands for longer service life, greater material compatibility and PFAS-independent lubrication concepts are encouraging a broader reassessment of established lubricant technologies. Rather than replacing existing high-performance solutions, modern silicone greases expand the range of available options, allowing engineers and formulators to select lubricants that best match the functional requirements of each application.
Ultimately, the future role of silicone greases will depend not on chemistry alone, but on continued advances in formulation design and a deeper understanding of the interaction between base oil, thickener architecture, solid lubricants and additive technology.
Dr. Eugenia Elzer is product manager at Setral Chemie GbH, where she supports the technical and strategic development of high-performance lubricants. She works closely with R&D, marketing and sales to align innovation with market requirements and customer expectations.