Adhesive Wear

Adhesive wear occurs when two surfaces slide against each other under pressure, leading to surface damage due to material transfer. Over time, this type of wear can trigger several failure modes that compromise component performance and reliability:

1. Galling: A severe form of adhesive wear where surfaces weld together and tear apart, often causing sudden equipment failure.
2. Scoring: Deep scratches or grooves appear along the contact path, increasing friction and reducing operational efficiency.
3. Seizing: Surfaces lock due to adhesive bonding, halting motion and potentially damaging bearings, shafts, or sliding elements.
4. Material Transfer: Friction causes particles to migrate from one part to another, leading to uneven wear and misalignment in precision systems.
5. Surface Fatigue: Repeated stress and micro-adhesion events can cause cracking and flaking over time, especially in high-cycle components.
6. Pitting: Localized adhesion breakdown creates small pits, which can grow and weaken the surface under continued stress.

To prevent adhesive wear failures, it’s essential to choose compatible materials, apply protective coatings, ensure proper lubrication, and follow routine maintenance protocols to minimize direct metal-to-metal contact.

Adhesive wear happens when two surfaces slide against each other under pressure. Microscopic welding occurs at contact points, leading to material transfer, galling, or surface scoring — especially in unlubricated or high-friction environments.

Cohesive wear, in contrast, originates from within the material itself. Internal forces — such as fatigue, thermal cycling, or residual stress — cause cracks or spalling to form below the surface, eventually releasing fragments without direct surface-to-surface abrasion.

• Adhesive wear: Caused by surface interaction and material transfer between parts.
• Cohesive wear: Caused by internal structural failure within the material.

Identifying the right wear type is critical: adhesive wear is often reduced with coatings and lubrication, while cohesive wear may require stronger base materials or improved heat and stress resistance.

Adhesive wear happens when metal surfaces in contact stick at microscopic points under pressure. As these surfaces slide, small fragments tear away, causing material transfer between parts. It’s common in gears, bearings, and components with sliding metal-to-metal contact.

Abrasive wear occurs when a harder material or foreign particles cut into the surface, removing material directly. This is typical in cutting, grinding, or contaminated environments like mining and drilling.

While both involve surface damage, adhesive wear is driven by material transfer, while abrasive wear removes material through cutting or plowing action.

Adhesion is explained by several mechanisms that describe how surfaces bond:

• Mechanical Interlocking: Adhesive fills surface irregularities, locking into microscopic pores to create a physical bond.
• Electrostatic Attraction: Oppositely charged surfaces generate electrostatic forces that help hold materials together.
• Diffusion: Molecules from the adhesive and substrate intermix at the interface, forming bonds through molecular entanglement.
• Chemical Bonding: Strong covalent, ionic, or hydrogen bonds form between the adhesive and substrate at the molecular level.

In real-world applications, multiple adhesion mechanisms often work together to create durable, reliable bonds.