The Surface-Topography Challenge: A Multi-Laboratory Benchmark Study to Advance the Characterization of Topography

Area of Science:

• Materials Science
• Metrology
• Surface Engineering

Background:

• Surface topography significantly impacts real-world applications and performance.
• Current standard practice often relies on single parameters like Ra (average absolute deviation), which can be scale-dependent and insufficient.
• Scale-dependent parameters are crucial for understanding visual appearance, friction, and wear.

Purpose of the Study:

• To highlight the necessity of multi-scale surface topography description.
• To evaluate the reliability of various metrology techniques.
• To establish consensus and best practices for surface characterization.

Main Methods:

• An international collaborative effort involving 153 scientists and engineers from 64 research groups across 20 countries.
• Characterization of statistically equivalent "rough" and "smooth" surface samples using diverse metrology techniques.
• Analysis of 2088 measurements to compile a comprehensive surface description.

Main Results:

• Significant disagreement in measurements when the lateral scale of measurement was ignored.
• Consensus was achieved by employing scale-dependent parameters and applying a resolution criterion.
• Data that deviated from majority measurements at each length scale was removed.

Conclusions:

• Ignoring the lateral scale of measurement leads to unreliable surface topography data.
• Scale-dependent parameters are essential for achieving consensus in surface characterization.
• The study provides recommended best practices for characterizing and specifying surface topography, with publicly released data for future research.