TiAlN coating has been used for many years to extend the lifetime and improve the
performance of cutting tools. It is applied using the PVD process which takes several
hours at temperatures of around 450 °C. Therefore, the tools on which the coating is
applied must be temperature resistant above this temperature.
As part of the diploma work, we investigated the effect of TiAlN coating on steel. In
the first part, we prepared and characterized samples from three different steels, on
which we later deposited TiAlN coating using the PVD process. Before applying the
coating, the samples were properly polished and cleaned. For D2 steel we prepared
additional samples covered with aluminium foil. This way, we found out whether such
local conditions occur in the deposition chamber that the microstructural properties of
steel change and subsequently decrease its hardness. After the coating deposition
was completed, we measured the nanohardness using instrumental indentation,
microhardness using the Vickers test, and macrohardness using the Rockwell test.
Optical microscopy was performed on all samples with a confocal optical microscope
and the topography of the substrate was constructed. The results were then
compared with each other, and we observed whether different substrates affect the
quality of the coating, and how the D2 steel changes during the deposition of the
coating.
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