Attempts to synthesise quaternary MAX phases (Zr,M)₂AlC and Zr₂(Al,A)C as a way to approach Zr₂AlC

Abstract

Despite having never been synthesized, the MAX phase Zr 2 AlC attracts a lot of interest owing to its foreseen properties. A possible way to circumvent this obstacle is to stabilize Zr 2 AlC by partially substituting one of its constituting elements. Here we report on attempts to synthesise quaternary MAX phases (Zr,M) 2 AlC and Zr 2 (Al,A)C where M = Cr, Ti or Mo and A = S, As, Sn, Sb and Pb. We were notably able to produce Zr 2 (Al 0. IntroductionThe MAX phases are a family of carbides and nitrides crystallizing with the hexagonal P6 3 /mmc structure in the general formula M n+1 AX n with n being an integer, M being an early transition metal, A being a group 13-16 element and X being C and/or N.[1] Around 70 ternary MAX phases can be synthesized as a bulk phase. More than half of known MAX phases with n = 1 were first reported in the 1960s by Nowotny et al. [2] and named 'H-phases'. They were almost completely ignored for two decades until Barsoum and El-Raghy renewed interest in 1996 by reporting the remarkable properties of Ti 3 SiC 2 ,[3] then demonstrating these properties were shared by the other MAX phases [4,5] and by finally defining the current 'MAX phase' appellation and definition.[6] Owing to their structure consisting of the stacking of n 'ceramic' layer(s) of MX interleaved by an A 'metallic' plane, MAX phases show a combination of both ceramic and metallic features (high thermal shock resistance, good machinability and high thermal and electrical conductivities, alike most metals; high decomposition or melting temperature, high elastic stiffness, and high oxidation and corrosion resistance as

Newly synthesized Zr 2 AlC, Zr 2 (Al 0.58 Bi 0.42 )C, Zr 2 (Al 0.2 Sn 0.8 )C, and Zr 2 (Al 0.3 Sb 0.7 )C MAX phases: A DFT based first-principles study

“…This is because it is expected to have high degree of neutron transparency because all the constituent atoms have small reaction cross-section for thermal neutrons, especially the Zr atom. It also has the potential to be used as a protective material in modified accident tolerant fuel [21]. Besides, this compound possesses the other generic features common to the MAX nanolaminates.…”

Does aluminum play well with others? Intrinsic Al-A alloying behavior in 211/312 MAX phases

“…mixing) entropy [9]. Entropic stabilization has been explored as a strategy to synthesize specific MAX phases that are metastable in their pure state, as the work by Horlait et al [15] on the attempted stabilization of (Zr, M) 2 AlC and Zr 2 (Al, A)C illustrates.…”

Toward Defect Engineering Strategies to Optimize Energy and Electronic Materials

“…In the past few decades of the miniaturization of devices, the introduction of more structurally complicated materials in conjunction with demanding processing and operating conditions have made the study of defects in materials increasingly important [1][2][3][4][5][6][7][8][9][10]. There is no single recipe of how to treat materials and what is the optimum concentration of defects.…”