Presence of Oxygen in Ti-Al-C MAX Phases-Based Materials and their Stability in Oxidizing Environment at Elevated Temperatures

Abstract

The Ti3AlC2-, (Ti,Nb)3AlC2-and Ti2AlC-based materials turned out to be more resistant than Crofer JDA steel in oxidizing atmosphere as 1000 h long tests at 600• C have shown. But the amounts of oxygen absorbed by the materials during testing were different. The Ti2AlC-based material demonstrated the lowest oxygen uptake, (Ti,Nb)3AlC2-based absorbed a somewhat higher amount and the highest amount was absorbed by Ti3AlC2-based material. Scanning electron microscopy and the Auger study witnessed that amounts of oxygen in the MAX phases before the exposure in air were as well different: the approximate stoichiometries of the matrix phases of materials were Ti3.1−3.2AlC2−2.2, Ti1.9−4Nb0.06−0.1AlC1.6−2.2O0.1−1.2 and Ti2.3−3.6AlC1−1.9O0.2−0.6, respectively. The higher amount of oxygen present in the MAX phase structures may be the reason for higher resistance to oxidation during long-term heating in air at elevated temperature. The studied materials demonstrated high stabilities in hydrogen atmosphere as well. The bending strength of the Ti3AlC2-and (Ti,Nb)3AlC2-based materials after keeping at 600• C in air and hydrogen increased by 10-15%, but the highest absolute value of bending strength before and after being kept in air and hydrogen demonstrated the Ti2AlC-based material (about 590 MPa).

The Influence of Oxygen Concentration during MAX Phases (Ti3AlC2) Preparation on the α-Al2O3 Microparticles Content and Specific Surface Area of Multilayered MXenes (Ti3C2Tx)

“…The 24 h conditioning of the powder mixture in Ar did not lead to desorption of the O 2 molecules. Aluminum has a high affinity to O 2 so in order to prepare perfect Ti 3 AlC 2 MAX phases, all preparation steps should be performed in an Ar filled glovebox [26].…”

Parameters of the Unit Cell of the Ti3AlC2 MAX‐Phase with Hydrogen

“…The procedure for the preparation of samples under different conditions is described elsewhere. [ 3 ] The X‐ray diffraction pattern of the sample is shown in Figure 1 . Miller indices ( hkl ) corresponding to maxima of diffraction are shown in this plot.…”

“…These materials are resistant to oxidation and corrosion. [3] Applications of MAX phases as protective coatings stimulated both experimental [4][5][6][7][8] and theoretical [9][10][11] research of the properties of these materials with different point defects. It is shown experimentally that Ti 3 AlC 2 , Ti 2 AlC, Ti 3 SiC 2 , and Ti 2 AlN MAX phases are promising materials for the application in nuclear reactors because they have high high-energy ion irradiation tolerance.…”

The Electrical Resistivity of Multiphase Systems Based on the Ti3AlC2 Hexagonal Phase at Low Temperatures

“…The procedure of the preparation of samples was described elsewhere. [4,6] The structure of samples was studied by means of X-ray diffraction. The phase composition of samples obtained by means of the Rietveld refinement method is shown in Table 1.…”

“…[1,2] It has high hardness and anticorrosion properties, which are characteristics for a ceramic material as well as low electrical resistivity, which is a characteristic for a metal. [3][4][5][6] Due to these properties, Ti 3 AlC 2 can be used in the wide range of applications, such as for the electromagnetic interference shielding, [7] for electrical contact applications, [8] as an absorber for the laser technique, [9] as materials with resistance of corrosion and oxidation, [3,4] and due to high mechanical damage tolerance and stability under the neutron irradiation. [10,11] For successful applications of the Ti 3 AlC 2 MAX phase in contemporary electronics, one should know mechanisms of scattering of electrons in this compound.…”