Reactive Synthesis of Polycrystalline Ti 3 AlC 2 and Its Sintering Behavior

Abstract

A method for fabrication of ternary compound Ti3AlC2 powder by pressureless calcining (PC) technique was developed. Powders of Ti, Al and TiC were mixed as staring materials. The effects of calcining temperature and aluminum content on the purity of Ti3AlC2 were discussed. The reaction mechanism and the microstructure evolution of Ti3AlC2 prepared at different temperatures were investigated by X-ray diffraction, field emission scanning electron microscopy and high resolution transmission electron microscopy. Results indicate that the single-phase polycrystalline Ti3AlC2 powders are obtained at 1300 °C , which possesses a typical laminated structure, and the best molar ratio of raw Ti/Al/TiC materials is 1:1.2:2. The bulk samples sintered by hot pressing were from the Ti3AlC2 powders. After hot pressing of different temperatures, the fully dense bulk Ti3AlC2 shows the best properties when prepared at 1300 °C. The density of bulk Ti3AlC2 reaches to 99.9%. The average Vickers hardness is around 5.7 GPa, and the maximum flexural strength is over 630 MPa. Finally the strengthening mechanism of the bulk Ti3AlC2 was also proposed.

Etching Mechanism of Monoatomic Aluminum Layers during MXene Synthesis

“…Figure S4 shows SEM images of the initial MAX phase powder sample with coexisting single-crystalline and polycrystalline particles. This mixture of single- and polycrystalline grains is formed by the high-temperature pressure-less sintering and subsequent milling of the green body in the synthesis process for Ti 3 AlC 2 . Polycrystalline grains can be distinguished by different single-crystalline grains connected to each other with different c -lattice orientations by weak grain boundaries.…”

“…This mixture of single-and polycrystalline grains is formed by the high-temperature pressure-less sintering and subsequent milling of the green body in the synthesis process for Ti 3 AlC 2 . 33 Polycrystalline grains can be distinguished by different single-crystalline grains connected to each other with different c-lattice orientations by weak grain boundaries. Void structures were also formed during the synthesis of the MAX phase (Figure S5).…”

Erosion Behavior of a Cu-Ti3AlC2 Cathode by Multi-Electric Arc

“…Copper powder (99.5%, ≤45 μm, Sinopharm Chemical Reagent Co., Ltd. Shanghai, China) and Ti 3 AlC 2 powder (99.2%, ~5 μm, for details on synthesis process, see [27]) were mixed for 3 h with a constant Cu/Ti 3 AlC 2 volume ratio of 80:20. The mixture was put into a high strength graphite mold.…”

Reactive hot pressing parameters on reaction, densification, and mechanical properties of Ti3AlC2 ceramic

“…It may be noted that the starting powders are elemental Ti, Al, carbon, or compounds such as Al 4 C 3 , TiC, etc. All the above‐specified (Table 1) approaches illustrate that the synthesis and sintering of Ti 3 AlC 2 in bulk and dense form need pressure in the range 25–50 MPa, temperature 1400°C–1600°C, and duration 30 min–16 h 2–7,9–12 . It is observed that the additional phase of TiC presents along with Ti 3 AlC 2 3–7,9,12 .…”

“…The starting raw materials, processing methods, experimental parameters, phases present, density, and mechanical properties of Ti 3 AlC 2 are given in Table 1 2–12 . It may be noted that the starting powders are elemental Ti, Al, carbon, or compounds such as Al 4 C 3 , TiC, etc.…”