liu.seSearch for publications in DiVA
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Ti2AlC coatings deposited by High Velocity Oxy-Fuel spraying
Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
Chalmers University of Technology, Microscopy and Microanalysis, Department of Applied Physics, Göteborg, Sweden.
University West, Department of Technology, Mathematics and Computer Science, Trollhättan, Sweden.
Kanthal AB, Hallstahammar, Sweden.
Show others and affiliations
2008 (English)In: Surface and Coatings Technology, ISSN 0257-8972, Vol. 202, no 24, 5976-5981 p.Article in journal (Refereed) Published
Abstract [en]

High Velocity Oxy-Fuel has been utilized to spray coatings from Ti2AlC (MAXTHAL 211®) powders. X-ray diffraction showed that the coatings consist predominantly of Ti2AlC with inclusions of the phases Ti3AlC2, TiC, and Al–Ti alloys. The fraction of Ti2AlC in coatings sprayed with a powder size of 38 μm was found to increase with decreasing power of the spraying flame as controlled by the total gas flow of H2 and O2. A more coarse powder (56 μm) is less sensitive to the total gas flow and retains higher volume fraction of MAX-phase in the coatings, however, at the expense of increasing porosity. X-ray pole figure measurements showed a preferred crystal orientation in the coatings with the Ti2AlC (000l) planes aligned to the substrate surface. Bending tests show a good adhesion to stainless steel substrates and indentation yields a hardness of 3–5 GPa for the coatings sprayed with a powder size of 38 μm.

Place, publisher, year, edition, pages
Elsevier , 2008. Vol. 202, no 24, 5976-5981 p.
Keyword [en]
MAX-phase, High Velocity Oxy-Fuel (HVOF), Phase transitions, X-ray diffraction, Scanning electron microscopy (SEM)
National Category
Engineering and Technology
Identifiers
URN: urn:nbn:se:liu:diva-13102DOI: 10.1016/j.surfcoat.2008.06.184OAI: oai:DiVA.org:liu-13102DiVA: diva2:17836
Available from: 2008-04-01 Created: 2008-04-01 Last updated: 2016-08-31
In thesis
1. Characterization of Ti2AlC coatings deposited with High Velocity Oxy-Fuel and Magnetron Sputtering Techniques
Open this publication in new window or tab >>Characterization of Ti2AlC coatings deposited with High Velocity Oxy-Fuel and Magnetron Sputtering Techniques
2008 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

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.
Series
Linköping Studies in Science and Technology. Thesis, ISSN 0280-7971 ; 1357
Keyword
MAX phase, Thermal Spray, PVD
National Category
Materials Engineering
Identifiers
urn:nbn:se:liu:diva-11422 (URN)978-91-7393-936-2 (ISBN)
Presentation
2008-04-24, Planc, Fysikhuset, Campus Valla, Linköpings universitet, Linköping, 10:15 (English)
Opponent
Supervisors
Note
Report code: LIU-TEK-LIC-2008:15.Available from: 2008-04-01 Created: 2008-04-01 Last updated: 2016-08-31
2. Thick and Thin Ti2AlC Coatings
Open this publication in new window or tab >>Thick and Thin Ti2AlC Coatings
2010 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

This Thesis explores the deposition techniques of magnetron sputtering and high velocity oxy-fuel (HVOF) spraying for Ti2AlC as a promising high-temperature material. Magnetron sputtering aims at producing thin (≤1 μm) Ti2AlC films of high crystal quality for use as a model system in understanding the material’s basic properties. HVOF is a new method for deposition of thick (≥200 μm) coatings by spraying Ti2AlC powder, with the aim of transferring the good bulk properties to coatings. The oxidation behavior of Ti2AlC coatings has been investigated for temperatures up to 1200 °C in air. As-deposited Ti2AlC(0001) thin films decompose into TiC during vacuum annealing at 700 °C by out-diffusion of Al as shown by x-ray diffraction analysis. The release of Al starts already at 500 °C in ambient air as driven by aluminum oxide formation on the film surface where the oxide initially forms clusters as observed by electron microscopy. While sputtering from a Ti2AlC target is simpler than by using different elemental targets, the resulting film composition differs from the target stoichiometry. This is due to differences in energy and angular distribution of the sputtered species and evaporation of Al at substrate temperatures above 700 °C. The composition can be compensated for by adding Ti to bind the Al and obtain phase-pure Ti2AlC coatings. For HVOF, I demonstrate how the total gas flow of a H2/O2 mixture (441-953 liter/min) and the powder grain size (30-56 μm) determine the thickness, density, and microstructure of the coatings. High gas flow and small grain size yield thick coatings of 210 μm with a low porosity of 2-8 % and a tensile stress of ≥80 MPa. A fraction of the Ti2AlC powder decomposes during spraying into TiC, Ti3AlC2, and Ti-Al alloys. The coatings also contain as much as 25 at.% O since the powder partly oxidizes during the spraying process. Increasing the powder size and decreasing the total gas flow yield a higher amount of Ti2AlC, but produces thinner coatings with lower cohesion. Post-annealing of the coatings at 900 °C in vacuum increases the Ti2AlC content due to a reversible phase transformation of the as-sprayed material. The high oxygen content, however, hinders the coating to completely transform into Ti2AlC and deteriorates its oxidation resistance. The work thus offers insights to the key parameters for optimizing Ti2AlC coating processing.

Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press, 2010. 63 p.
Series
Linköping Studies in Science and Technology. Dissertations, ISSN 0345-7524 ; 1328
National Category
Natural Sciences
Identifiers
urn:nbn:se:liu:diva-57525 (URN)978-91-7393-356-8 (ISBN)
Public defence
2010-09-03, Planck, Fysikhuset, Campus Valla, Linköpings universitet, Linköping, 10:15
Opponent
Supervisors
Available from: 2010-06-22 Created: 2010-06-22 Last updated: 2016-08-31Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Authority records BETA

Frodelius, JennyHögberg, HansHultman, Lars

Search in DiVA

By author/editor
Frodelius, JennyHögberg, HansHultman, Lars
By organisation
Thin Film PhysicsThe Institute of Technology
Engineering and Technology

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 231 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf