Scratch hardness Scratch hardness Scratch hardness tests are used to determine the hardness of a material to scratches and abrasion. The earliest test was developed by mineralogist Friedrich Mohs in 1820 (see Mohs scale). It is based on relative scratch hardness, with talc assigned a value of 1 and diamond assigned a value of 10. Mohs' scale had two limitations; it was not linear, and most modern abrasives fall between 9 and 10. Raymond R. Ridgway, a research engineer at the Norton Company, modified the Mohs scale by giving garnet a hardness of 10 and diamond a hardness of 15. Charles E.
Leeb rebound hardness test Leeb rebound hardness test The Leeb Rebound Hardness Test (LRHT) is one of the four most used methods for testing metal hardness. This portable method is mainly used for testing sufficiently large workpieces (mainly above 1 kg). It measures the coefficient of restitution. It is a form of nondestructive testing. The Leeb rebound hardness test method was developed in year 1975 by Leeb and Brandestini at Proceq SA to provide a portable hardness test for metals. It was developed as an alternative to the unwieldy and sometimes intricate traditional hardness measuring equipment. The first Leeb rebound product on the market