rajavoitelua

Rajavoitelua is a Finnish term that translates to "border lubrication" or "boundary lubrication." It refers to a condition in mechanical systems where a thin film of lubricant exists between moving surfaces, but this film is not thick enough to completely prevent direct contact. In this state, wear can occur, but it is typically reduced compared to situations with no lubrication at all.

The boundary lubrication regime is characterized by the presence of adsorbed layers of lubricant molecules on the metal surfaces. These adsorbed layers act as a barrier, preventing catastrophic seizure of the components. However, the surface asperities, microscopic high points on the surfaces, can still come into intermittent contact. The effectiveness of boundary lubrication depends on the properties of the lubricant, such as its viscosity and the presence of extreme pressure additives, as well as the surface characteristics of the materials in contact.

This mode of lubrication is commonly encountered in various applications, including gearboxes, engines, and bearings, particularly during start-up and shut-down, or under high load conditions where full fluid film lubrication might not be maintained. Understanding and managing rajavoitelua is crucial for predicting and mitigating wear, extending the service life of mechanical components, and ensuring the reliability of machinery. Lubricant selection and system design play significant roles in minimizing the negative effects associated with this lubrication regime.