An ASTM standard for quantitative scratch adhesion testing of thin, hard ceramic coatings

Thin, hard ceramic coatings on metals and ceramics are extensively used for wear and abrasion resistance, friction control, corrosion resistance, and tailored functional (electrical, optical, and magnetic) properties across a wide range of high-performance applications. Coating producers and users have to measure and control the coating-substrate adhesion strength, because adhesion failure is often the primary failure mechanism of the coating, limiting its performance and life. The quantitative test method of choice for thin hard coatings is scratch adhesion testing. In this technique, a diamond stylus is drawn across the coating on the surface under increasing normal load and the damage to the coating is assessed against the applied load. With DOE funding and in coordination with the ASTM Committees C28, G08, and B02, a new scratch adhesion test standard has been researched and written and has been published. The ASTM C1624 test standard (Adhesion Strength and Mechanical Failure Modes of Ceramic Coatings by Quantitative Scratch Testing) provides comprehensive and detailed guidance and instructions on scratch adhesion testing of thin, hard ceramic coatings-the principles, terminology, applications, limitations, equipment, specimen preparation and characterization, critical experimental factors, calibration, procedures, calculations, and reporting requirements.