The measurement of volumetric surface properties is most commonly encountered in the wear analysis of lubricated surfaces. However, the application of this method is much broader - from adhesion, porosity to particle distribution.
Material wear analysis
When it comes to tribological studies, understanding and quantifying wear scratches is critical to understanding the big picture. ZYGO's 3D optical profiling systems enable the segmentation of linear wear defects from the unworn area and provide quantitative metrics. Commonly tracked metrics include:
- Volume (positive and negative)
- maximum & average depth/height
- area and position
Surface Texture Description & Material Proportion Analysis
Another integral part of tribological studies is the ability to accurately describe and quantify surface finish. This is because texture has a major impact on surface functionality. Traditionally, surface description is almost exclusively associated with average roughness (Ra or Sa). By including other equally important characteristics such as skewness (Ssk), skewness (Sku; kurtosis), or parameters to describe material properties, we can achieve a deeper understanding of surface properties and their effective use.
Material proportion analysis, often called the Abbott-Firestone curve, examines the surface distribution as a function of height. This information can be particularly useful when describing, for example, multilayered surfaces such as engine cylinder walls. Examples of applications of this method include the use of reduced valley depth (Svk) to understand the ability of a surface to retain lubrication, or, for example, the analysis of the current lubrication state of a surface through the invalid valley volume parameter of the constrained surface scale and the invalid core volume of the constrained surface scale (Vvc and Vvv).
