Synthesis process and mechanical, tribological and electro-tribological performance of Ti2AlC and Ti3AlC2 MAX phases thin films for applications as sliding electrical contacts

R. Quispe Dominguez^{1, 2, 3, *}, C. E. Torres Fernandez², M. Hopfeld⁴, A. Rosenkranz⁵, P. Schaaf⁴, R. Grieseler²

¹ Universidad Nacional de San Antonio Abad del Cusco, Perú, ² Pontificia Universidad Católica del Perú, Perú. ³ Universidad Continental Filial Cusco, Perú, ⁴ Technische Universität Ilmenau, Germany, ⁵ Universidad de Chile, Chile.

*roger.quisped@unsaac.edu.pe

Mn+1AXn (short: MAX) phases are ternary carbides and nitrides with a hexagonal crystal structure. They possess an interesting combination of metallic and ceramic properties, such as high electrical and thermal conductivity, high mechanical strength, and chemical resistance [1]. Therefore, MAX phases are a highly interesting material as protective coatings, sliding electrical contacts and solid lubricants for tribological applications [2]. Moreover, MAX phases are known to have self-healing abilities to some extent. To take advantage of these properties, thin films can be prepared on a wide range of substrates using various methods. Magnetron sputtering is one of the most commonly used techniques these days [3]. The talk presents the most recent findings on the tribological performance and wear rate of Ti2AlC and Ti3AlC2 MAX phases [4]. The two MAX phases thin films have been synthesized by magnetron sputtering, following a multilayer approach of single elements of required stoichiometry and subsequent rapid thermal annealing.

The tribological properties of these thin films with a total thickness of around 500 nm were measured using a reciprocating micro-tribometer against a 100Cr6 steel ball under different normal loads. Furthermore, the electro-tribological test was carried out using a ball-on-flat reciprocating tribometer under electrical currents of 10, 50 and 100 mA. The coefficient of friction and the electrical contact resistance were measured simultaneously in the same test. Connecting the coefficient of friction and electrical contact resistance to the crystal structure, hardness, roughness, grain size, resistivity and mechanical properties of MAX phase thin films can provide new insights into the tribological, electro-tribological and sliding electrical contacts performance of these materials.

References

[1] M.W. Barsoum, Prog. Solid St. Chem. 2000, 28, 201.

[2] M. Hopfeld, R. Grieseler, A. Vogel, H. Romanus, and P. Schaaf, Surf Coat Technol, 2014, 257, 286.

[3] C. Torres, R. Quispe, N.Z. Calderón, L. Eggert, M. Hopfeld, C. Rojas, M.K. Camargo, A. Bund, P. Schaaf, and R. Grieseler, Appl Surf Sci, 2021, 537, 147864.

[4] R. Quispe, C. Torres, L. Eggert, G.A. Ccama, M. Kurniawan, M. Hopfeld, J.L. Zárate, M.K. Camargo, A. Rosenkranz, J.A. Acosta, A. Bund, P. Schaaf, and R. Grieseler, Adv Eng Mater, 2022, 2200188.