First-order Raman scattering of the MAX phases Ta4AlC3, Nb4AlC3, Ti4AlN3, and Ta2AlC
2012 (English)In: Journal of Raman Spectroscopy, ISSN 0377-0486, E-ISSN 1097-4555, Vol. 43, no 7, 954-958 p.Article in journal (Refereed) Published
Herein, we report on the Raman spectra of the following ternary hexagonal carbides and nitrides (MAX phases): Ta4AlC3, Ta2AlC and Ti4AlN3. We also present the Raman-active modes of a- and beta-Ta4AlC3, Nb4AlC3 and Ti4AlN3, also referred to as the 413 MAX phases as predicted from first principles calculations using density functional theory. We compare the obtained experimental and calculated results with previous studies on Ta2AlC and Ti4AlN3. The vibrational behavior associated with the Raman-active modes for the 413 phases has been identified for the first time. In general, the agreement is good between theory and experiment. The experimental and calculated results indicate that the modes at low wavenumbers - dominated by the Al atoms - are a weak function of chemistry and the differences in energy can be traced to variations in the reduced mass. The modes at higher wavenumbers are dominated by the C and N atoms and show a strong dependence on the unit cell chemistry, with the TaC bond being stiffer than the NbC bond, which is in turn stiffer than TiN.
Place, publisher, year, edition, pages
John Wiley and Sons , 2012. Vol. 43, no 7, 954-958 p.
ternary carbides, MAX phase, polymorphism
Engineering and Technology
IdentifiersURN: urn:nbn:se:liu:diva-79983DOI: 10.1002/jrs.3101ISI: 000306570400020OAI: oai:DiVA.org:liu-79983DiVA: diva2:544949
Funding Agencies|Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Vehicle Technologies of the US Department of Energy under the Batteries for Advanced Transportation Technologies (BATT) Program|DE-AC02-05CH112316951370|Integrated Graduate Education and Research Traineeship (IGERT) under NSF|DGE-0654313|Swedish Foundation for Strategic Research (SSF)||European and Swedish Research Councils||Government Strategic Research Area Grant in Materials Science||Alexander von Humboldt Foundation||2012-08-172012-08-172016-08-31