Characterization of Ti2AlC coatings deposited with High Velocity Oxy-Fuel and Magnetron Sputtering Techniques
2008 (English)Licentiate thesis, comprehensive summary (Other academic)
This Thesis presents two different deposition techniques for the synthesis of Ti2AlC coatings. First, I have fabricated Ti2AlC coatings by high velocity oxy-fuel (HVOF) spraying. Analysis with scanning electron microscopy (SEM) show dense coatings with thicknesses of ~150 µm when spraying with a MAXTHAL 211TM Ti2AlC powder of size ~38 µm in an H2/O2 gas flow. The films showed good adhesion to stainless steel substrates as determined by bending tests and the hardness was 3-5 GPa. X-ray diffraction (XRD) detected minority phases of Ti3AlC2, TiC, and AlxTiy alloys. The use of a larger powder size of 56 µm resulted in an increased amount of cracks and delaminations in the coatings. This was explained by less melted material, which is needed as a binding material. Second, magnetron sputtering of thin films was performed with a MAXTHAL 211TM Ti2AlC compound target. Depositions were made at substrate temperatures between ambient and 1000 °C. Elastic recoil detection analysis (ERDA) shows that the films exhibit a C composition between 42 and 52 at% which differs from the nominal composition of 25 at% for the Ti2AlC-target. The Al content, in turn, depends on the substrate temperature as Al is likely to start to evaporate around 700 °C. Co-sputtering with Ti target at a temperature of 700 °C, however, yielded Ti2AlC films with only minority contents of TiC. Thus, the addition of Ti is suggested to have two beneficial roles of balancing out excess of C and to retain Al by providing for more stoichiometric Ti2AlC synthesis conditions. Transmission electron microscopy and X-ray pole figures show that the Ti2AlC grains grow in two preferred orientations; epitaxial Ti2AlC (0001) // Al2O3 (0001) and with 37° tilted basal planes of Ti2AlC (101̅7) // Al2O3 (0001).
Place, publisher, year, edition, pages
Institutionen för fysik, kemi och biologi , 2008. , 30 p.
Linköping Studies in Science and Technology. Thesis, ISSN 0280-7971 ; 1357
MAX phase, Thermal Spray, PVD
National CategoryMaterials Engineering
IdentifiersURN: urn:nbn:se:liu:diva-11422ISBN: 978-91-7393-936-2OAI: oai:DiVA.org:liu-11422DiVA: diva2:17838
2008-04-24, Planc, Fysikhuset, Campus Valla, Linköpings universitet, Linköping, 10:15 (English)
Emmerlich, Jens, Dr.
Report code: LIU-TEK-LIC-2008:15.2008-04-012008-04-012009-04-27
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