Grit hardness is usually tested by a Knoop micro indenter test [SCHT81, MENA00]. By means of an electrostatic separator, particles with conductive surfaces can be selected. Capillarity is a measure for the wettability of abrasive grits [UAMA09, SCHT81]. Capillarity gives an indication of grit cleanliness and is particularly important for aqueous glues for coated abrasive tools [UAMA09]. The test procedure foresees to fill glass tubes with the grit sample and measure the capillarity height of water [SCHT81, ANSI64].
Several chemical analyses are in practice, such as atomic absorption, emission spectroscopy, and X-ray fluorescence [MENA00]. Silicon carbide can be heated in a 27 % potassium hydroxide solution for 9 h to detect free silicon dioxide [SCHT81]. Other chemical analyses are based on classical wet methods, such as FEPA 46/93, ISO 9285, and ANSI B74.14 for fused aluminum oxides and ISO 9286, FEPA 45/93, and ANSI B74.15 for silicon carbides [ANSI86, MENA00].