Processing of MAX phases: From synthesis to applications

Abstract

MAX phases are well-known and established due to their unique combination of properties and versatility, but this family of materials has experienced several ups and downs during its short history, including even being referred to with different names. Extensive work was carried out in the early 1960s in Vienna (Austria) by Wolfgang Jeitschko and Hans Nowotny, who discovered in more than 100 new carbides and nitrides. 1 Among them, they reported a new class of ternary systems, based on a transition metal (M), a metalloid (Me), and carbon (C), with a similar crystal structure to carbon-stabilized β-manganese phase, that is, Mo 3 Al 2 C. They were classified as "H-Phases" due to their hexagonal crystal structure, and some compositions

Theoretical predictions on temperature‐dependent strength for MAX phases

“…1,2 MAX phases have also been called as "Cermets", because they combine some merits of ceramics (such as high-temperature mechanical properties, good oxidation resistance, and corrosion resistance), with those of metals (such as thermal shock resistance, damage tolerance and good electrical and thermal conductivity, machinability). 1,3 Due to the remarkable properties of some MAX phases especially high-temperature strength, thermal shock resistance, damage tolerance, and oxidation…”

Ceramic materials for energy conversion and storage: A perspective

“…In the high‐temperature range typically above 1000°C (as found in gas turbines and concentrated solar power), there is hardly any competition with other types of materials. Under the harshest conditions, even new structural ceramic materials such as CMCs 3 and MAX phases 22 need protective layers, of course out of stable oxide ceramics. For other applications, especially fuel cells and electrolysis, separation membranes, and batteries, other material classes cannot be neglected.…”

Strategies for Fabricating High‐Performance Electrochemical Energy‐Storage Devices by MXenes

“…The typical chemical formulas of MAX phases (normally a group of layered ternary carbides and nitrides, also known as the precursors) and MXenes are expressed as M n + 1 AX n and M n + 1 X n T x (n = 1, 2, 3 or 4), in which M and A represent early transition metals (e. g., Ti, V, Cr, Hf) and group IIIA or IVA elements (e. g., Al, Ga, Si, Sn), respectively. [15] In addition, X is carbon, nitrogen or both, and T x (which sometimes is not shown in the formula of MXenes) represents the surface terminations (e. g., À OH, À F), as shown in Figure 1 (a). [16] Regarding the structure of MAX phases, the octahedral M n + 1 X n and A layers are alternatively stacked along the c direction.…”