Molten salt dynamic sealing synthesis of MAX phases (Ti3AlC2, Ti3SiC2 et al.) powder in air. Issue 1 (1st January 2023)

• Record Type: Journal Article
• Authors: Liu, Zetan; Xu, Jingkun; Xi, Xiaoqing; Luo, Weijia; Zhou, Ji
• Is Part Of: Ceramics international. Volume 49:Issue 1(2023)
• Page Start: 168
• Page End: 178
• Publication Date: 2023-01-01
• Subjects: MAX phases -- Powder synthesis -- Molten salt -- Dynamic liquid sealing; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2022.08.325
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: Since the synthesis of non-oxidized ceramic and alloy powders requires both high temperature and oxygen insulation conditions, here we demonstrate a cost-efficient molten salt sealing/shielded synthesis method with dynamic gas tightness. Compared to conventional synthesis method, it can prevent the loss of reaction materials at high temperature, cut off the connection between reacting material and outside air, and does not require long-time ball milling mixing treatment or provision of applied pressing before or during heating. Only low-cost salts (e.g., NaCl, KCl), a few minutes of raw material mixing, and regular heating molds are required to obtain high-purity (>96 wt%), micron-sized Ti3 AlC2 and Ti3 SiC2 powders with narrow size distribution, which significantly decreased the complexity and production costs in the synthesis process. The effect of temperature and raw material content on the products were investigated. The mechanism of diffusion reaction between reactants in molten salt environment was analyzed. The new method developed here was also applicable to Ti2 AlC, V2 AlC and Cr2 AlC MAX phases, as well as provided new ideas for the preparation of other MXenes precursors with certain stoichiometric ratios, air-sensitive materials and nanopowders.