AutoMHT

Automatic Microhardness-Tester for Optical Microscopes

Microhardness measurements represent an important possibility for the analysis and characterisation in solid state physics and are routinely used in particular on fibres or on thin films.

In the Thin film Group (Institute of Solid State Physics; Technical University of Vienna) a microhardness tester has been used for more than two decades on an optical microscope for the determination of microhardness values of various coatings. The evaluation takes place visually and is carried out by the operator. The hardness impression which a measuring diamond leaves in the surface must be evaluated by means of an eyepiece micrometer. The size of the impression is only in the order of a few µm. These subjective measurements cause possible mistakes which negatively affect the quality of the work. Moreover, the visual work on the microscope is very tiring which complicates long time series.

Therefore, the existing microhardness tester has been brought on the newest state of the technology by a student’s final work at the HTBL Hollabrunn. The control of the measuring instrument (at present an external control device) had been replaced by a standard PC and has been realized in LabView. For the automatic evaluation of the pictures of the measuring impressions (by means of a CCD camera) an analysis software has been written (also in LabView).

In conclusion the possibility and limits of automatic measurements have been evaluated and documented by typical samples from scientific work (thin films, cross section preparations, surfaces).

This project has been completed.