Round robin for testing instrumented indenters with silicon reference springs

For the traceability of hardness and elasticity measurements with instrumented indenters to SI units, a measuring standard based on a silicon bending spring with a stop limit exists. Besides the bending stiffness of the spring, the bending point of the measured force–displacement curve at the stop limit can be used as an additional calibration point for both the probing force and the displacement. In a round-robin test with six participants and seven devices the bending stiffness, the bending force and the bending deflection were measured and compared. The result of the bending stiffness, the bending force and the bending deflection agree within ±2.8 %, ±4.2 % and ±3.2 %, respectively.