HARDNESS MEASURING WITH A DIAMOND INDENTER HAVING SURFACE TREATMENT OR COATING

摘要

A device and method of hardness measuring in which a diamond indenter (1) is coated with a hard electrically conductive outer surface layer (3, 7). The indenter is pressured into the surface being measured in the conventional manner. The physical size of the indentation is measured, or a predetermined physical size of the indentation obtained, by one of two indenter arrangements. One is by measuring the electrical resistance of the indenter coating (7) between the distal end of the conductive layer and the surface of the sample being tested. The other is by stopping advance of the indenter (1) when electrical continuity is obtained between the sample and an edge of the indenter coating (4) which is some distance from the apex. Where the sample being tested is not itself electrically conductive an electrically conductive layer is applied to the sample surface before testing is commenced.