Hot-pressing Sintering of Double-A-layer MAX Phase Mo2Ga2C
(2.School of Mechanical and Power Engineering, Henan Polytechnic University, Jiaozuo, China 454003)
【Abstract】Mo2Ga2C, a double-A-layer MAX, is reported to be films or powders. This paper researched the sintering properties of M2Ga2C powders to make dense bulk samples by vacuum hot-pressing sintering. It was found that 750 °C was a suitable sintering temperature, while higher temperature (850 °C) resulted in decomposition of Mo2Ga2C yielding to main product of Mo2C. During sintering process at 750 °C, its grain size did not increase obviously with sintering time; meanwhile, the size of pores decreased markedly and the relative density increased significantly with the increasing sintering time. Additionally, the hot-pressed samples had obvious texture. Due to layering, some grains changed their orientations during sintering, of which most of the (00l) planes in the hot-pressed samples preferred to be perpendicular to the direction of hot-pressing sintering. Almost fully dense Mo2Ga2C bulk (relative density: 98.8%) was obtained by hot-pressing sintering at 750 °C for 8 h. This advantage of the method suggests that it can serve as promising preparation for Mo2Ga2C, a double-A-layer MAX.
【Keywords】 MAX phase; Mo2Ga2C; sintering; hot press;
(Translated by SUN Z)
 HU C, LAI C. C, TAO Q, et al. Mo2Ga2C: a new ternary nanolaminated carbide. Chemical Communications, 2015, 51 (30): 6560–6563.
 BARSOUM M W, BRODKIN D, EL T. Layered machinable ceramics for high temperature applications. Scripta Materialia, 1997, 36 (5): 535–541.
 BARSOUM MICHEL W, RADOVIC MILADIN. Elastic and mechanical properties of the MAX phases. Annual Review of Materials Research, 2011, 41 (41): 195–227.
 LI MIAN, LI YOU-BiING, LUO KAN, et al. Synthesis of novel MAX phase Ti3ZnC2 via A-site-element-substitution approach. Journal of Inorganic Materials, 2019, 34 (1): 60–64.
 LI JIAN-HUA, ZHANG CHAO, WANG XIAO-HUI. Progress in machinable and electrically conductive laminate ternary ceramics (MAX phases). Advanced Ceramics, 2017, 38 (1): 3–20.
 LIANG BAO-YAN, ZHANG WANG-XI, WANG YAN-ZHI, et al. Reaction mechanism of fabrication of MAX-cBN composites by microwave sintering. Materials Reports, 2016, 30 (6): 66–69.
 LIU YAO, ZHANG JIAN-BO, LI YONG, et al. The status and progress of MAX/Metallic matrix self-lubricating composite. Materials Reports, 2015 (S2): 517–523.
 ZHOU AI-GUO, LI ZHENG-YANG, LI LIANG, et al. Preparation and microstructure of Ti3SiC2 bonded cubic boron nitride superhard composites. Journal of the Chinese Ceramic Society, 2014,42 (2): 220–224.
 ZHU YUAN-YUAN, ZHOU AI-GUO, JI YI-QIU, et al. Tribological properties of Ti3SiC2 coupled with different counterfaces. Ceramics International, 2015, 41 (5): 6950–6955.
 LI ZHENG-YANG, ZHOU AI-GUO, LI LIANG, et al. Synthesis and characterization of novel Ti3SiC2–cBN composites. Diamond and Related Materials, 2014, 43: 29–33.
 LI LIANG, ZHOU AI-GUO, WANG LI-BO, et al. In situ synthesis of cBN–Ti3AlC2 composites by high-pressure and high-temperature technology. Diamond and Related Materials, 2012, 29: 8–12.
 LI MIAN, LU JUN, LUO KAN, et al. Element replacement approach by reaction with Lewis acidic molten salts to synthesize nanolaminated MAX phases and MXenes. Journal of the American Chemical Society, 2019, 141 (11): 4730–4737.
 LI MIAN, LI YOU-BING, LUO KAN, et al. Synthesis of novel MAX phase Ti3ZnC2 via A-site-element-substitution approach. Journal of Inorganic Materials, 2019, 34 (1): 63–67.
 LU JIN-RONG, ZHOU YANG, LI HAI-YAN, et al. Wettability and wetting process in Cu/Ti3SiC2 system. Journal of Inorganic Material, 2014, 29 (12): 1313–1319.
 THORE A, DAHLQVIST M, ALLING B, et al. Phase stability of the nanolaminates V2Ga2C and (Mo1–xVx)2Ga2C from first-principles calculations. Physical Chemistry Chemical Physics, 2016, 18 (18): 12682.
 FASHANDI H, LAI C C, DAHLQVIST M, et al. Ti2Au2C and Ti3Au2C2 formed by solid state reaction of gold with Ti2AlC and Ti3AlC2. Chemical Communications, 2017, 53: 9554–9557.
 LAI C C, MESHKIAN R, DAHLQVIST M, et al. Structural and chemical determination of the new nanolaminated carbide Mo2Ga2C from first principles and materials analysis. Acta Materialia, 2015, 99 (15): 157–164.
 ALI M A, KHATUN M R, JAHAN N, et al. Comparative study of Mo2Ga2C with superconducting MAX phase Mo2GaC: first-principles calculations. Chinese Physics B, 2017, 26 (3): 297–302.
 CHAIX-PLUCHERY O, THORE A, KOTA S, et al. First-order Raman scattering in three-layered Mo-based ternaries: MoAlB, Mo2Ga2C and Mo2GaC. Journal of Raman Spectroscopy, 2017, 48: 631–638.
 WANG HAI-CHEN, WANG JIA-NING, SHI XUE-FENG, et al. Possible new metastable Mo2Ga2C and its phase transition under pressure: a density functional prediction. Journal of Materials Science, 2016, 51 (18): 1–9.
 HE HONG-TIAN, JIN SEN, FAN GUANG-XIN, et al. Synthesis mechanisms and thermal stability of ternary carbide Mo2Ga2C. Ceramics International, 2018, 44 (18): 22289–22296.