By Craig Winterfield
Traditional oil analysis using ICP Spectrometry is limited because it groups all particles together, regardless of source, into one ICP result for each element. Different wear mechanisms generate particles of different sizes, shape, surface structure and elemental composition. Determining this information for each particle individually is critical for predictive maintenance and failure analysis.
Abnormal Wear
Abnormal wear can include cutting and abrasive wear, severe sliding wear, fatigue wear, adhesive wear, and severe spalling. Three-body cutting wear is caused by the presence of abrasive particles in the oil causing wear between two surfaces. Two-body cutting wear occurs when one surface directly cuts into another and can be caused by a misalignment or component damage. These particles have a characteristic corkscrew or C shape and are easy to identify visually but are missed by ICP and PQ index.
Severe sliding wear particles show visible striations along their major axis. These are generated when surface contact occurs when components are subjected to excessive loading or high speeds causing particles to break off.
Normal Wear
Some wear particles are considered to be Normal Wear and are not a cause for concern. New or rebuilt components may generate long thin bar shaped particles called Break-in Wear. These particles will subside after the break-in period has passed. Elements with rolling contact such as bearings will produce small laminar platelets as well as normal rubbing/sliding wear <10um. These particles are considered normal and action is not required.
Differentiating Wear with SEM-EDS
Differentiating between these normal and abnormal particles requires each particle to be analyzed individually for size, shape and composition. By combining SEM-EDS technology with advanced AI and automated software it is possible to analyzed hundreds of particles individually and therefore provide a clear picture of machine health and operating condition.
Learn more about SEM-EDS wear debris analysis. Contact a Fluid Life representative.