To prevent metal-to-metal contact in hydraulic fluids, what is a crucial property?

The crucial property that helps prevent metal-to-metal contact in hydraulic fluids is film strength. Film strength refers to the ability of a lubricant to maintain a protective film between two surfaces, thereby preventing direct contact. This is essential in hydraulic systems where moving parts operate under high pressure and speed. A strong lubricant film significantly reduces wear and tear on the components, leading to increased efficiency and lifespan of the system.

In hydraulic applications, the film strength ensures that even under load, a sufficient layer of hydraulic fluid remains between surfaces, preventing metal-to-metal contact that can cause damage. Adequate film strength helps minimize friction and allows the hydraulic components to operate smoothly, contributing to overall system reliability.

While the other properties mentioned may play roles in different contexts, they do not directly relate to the primary function of preventing metal-to-metal contact as effectively as film strength does. Low viscosity might lead to inadequate film formation under high pressure, high density does not guarantee the presence of a protective film, and low temperature stability does not directly relate to the prevention of contact between moving parts.