Recording Microhardness Of Glasses - Results Of A Round Robin

Recording microhardness is being more widely used, but is still relatively new. Accordingly, TC 6 of the ICG carried out a round-robin experiment to learn more about reproducibility of results. Six laboratories took part. All used similar conditions, i.e., a penetration rate of less than 0.1um s-1, and a maximum load of 2N. The recording hardness HU [1] calculated from the penetration depth at the maximum force showed big differences among the laboratories. However, excellent agreement was obtained when two-parameter polynomial functions were used for fitting the force/depth curve, F(h).