Possibilities of hardness measurement of composite coating based on PTFE with Al2O3 particles applied on aluminium substrate
2020
Svobodova, J., Jan Evangelista Purkyne Univ. in Usti nad Labem (Czech Republic) | Lysonkova, I., Jan Evangelista Purkyne Univ. in Usti nad Labem (Czech Republic)
The importance of surface treatment is emphasized by new knowledge from the preparation of coatings and thin films. These coatings can influence basic properties, such as corrosion resistance, surface friction characteristics, hardness and many others. This paper pays attention to the evaluation of the hardness of the polytetrafluoroethylene-based composite coating with the addition of micro and nano aluminium oxide particles at various concentrations. The experiment describes the testing of composite coatings PTFE + Al2O3 at concentrations of 0.1 %•lE−1, 0.01 %•lE−1, 0.001 %•lE−1 by various methods of hardness measurement and their evaluation by SEM. The hardness of the coating thus prepared was influenced by its thickness. For measurements the nanoindentation test and Vickers hardness test were used. The measurement results were also influenced by the chosen coating technology, which influenced the uniformity of the distribution of particles in the coating. To verify the uniformity of the particles in the evaluation of individual samples the SEM analysis was used. The distribution of particles in the coating has the effect of influencing the properties of the coating, not only the hardness, but also, for example, the abrasion resistance, roughness etc. The most suitable method for evaluating the hardness of a tested coating is the nanoindentation test, which has proved to be the most suitable method. Values are influenced by the injection point, i.e. whether there was an Al2O3 cluster or only a Teflon coating in the area. We confirmed the assumption of uneven distribution of particles and their aggregation using electron microscope documentation. The experimentally verified results are discussed at the end of this paper and there are given individual conclusions and recommendations.
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