TEM investigation of tribo-oxide particles

D. JENKO, W. TUCKART, N. FOCHESATTO, H. SVOBODA, A. JUAN AND M. JENKO

Dubrovmik

Congreso; 4th Joint Vacuum Conference, EVC-12, 12th European Vacuum Conference, AMDVG- 11, 11th Annual Meeting of the German Vacuum Society, CroSloVM-19, 9th Croatian- Slovenian Vacuum Meeting; 2012

IUVSTA

Two series of tribology specimens were analyzed in details by means of conventional and high-resolution transmission electron microscopy (CTEM and HR TEM) to find differences in morphology and composition of tribo-oxide particles. The first series of specimens were untreated material and the second series were the material with 25 % of martensite phase, treated at 810 (critical annealing temperature). Both series of the specimens were obtained from tribology test made at 5 N of applied load. Correct indentification of iron oxides present in the specimens is important because the cause and remedy for different forms of corrosion are different According to the results of chemical composition analyses obtained by means of energy dispersive X-ray spectroscopy (EDS) the approximate temperature range during the tribology test could be estimated. The presence of different oxides could help to evaluate this temperature range. We performed EDS analyses on different areas of the same particle and also on different particles. The analyses showed there are probably all three previously mentioned iron oxides present and also some other different ratios of iron to oxygen. Scanning transmission electron microscopy (STEM) analyses using bright-field (BF) detector were performed as well. The distribution of iron and oxygen in some particles is shown on EDS elemental mappings, line profiles and line analyses. The results of line profiles and line analyses showed that the composition in the majority of chosen particles is not the same through the whole volume