Which of the following is a common cause of adhesive wear?

Adhesive wear occurs when two surfaces in contact slide against each other, and the bonding between the materials can lead to material transfer from one surface to another. The wrong viscosity of lubricants can significantly contribute to this type of wear.

When lubricant viscosity is inappropriate, it affects the film strength and the ability of the lubricant to separate the surfaces adequately. If the viscosity is too low, it may not create a sufficient protective barrier, allowing the metal surfaces to make contact and generate adhesive wear. Conversely, if the viscosity is too high, it may not flow properly to the contact surfaces, again failing to provide adequate protection.

In this context, while factors like excessive lubrication volume, high temperature operations, and the presence of water in the lubricant can influence wear mechanisms, the specific impact of incorrect lubricant viscosity directly relates to the formation of conditions that encourage adhesive wear.