Progress in research and development on MAX phases: a family of layered ternary compounds

Abstract

The MAX phases are a group of layered ternary compounds with the general formula M nz1 AX n (M: early transition metal; A: group A element; X: C and/or N; n51-3), which combine some properties of metals, such as good electrical and thermal conductivity, machinability, low hardness, thermal shock resistance and damage tolerance, with those of ceramics, such as high elastic moduli, high temperature strength, and oxidation and corrosion resistance. The publication of papers on the MAX phases has shown an almost exponential increase in the past decade. The existence of further MAX phases has been reported or proposed. In addition to surveying this activity, the synthesis of MAX phases in the forms of bulk, films and powders is reviewed, together with their physical, mechanical and corrosion/oxidation properties. Recent research and development has revealed potential for the practical application of the MAX phases (particularly using the pressureless sintering and physical vapour deposition coating routes) as well as of MAX based composites. The challenges for the immediate future are to explore further and characterise the MAX phases reported to date and to make further progress in facilitating their industrial application.

Synthesis of high-purity Ti2SC powder by microwave hybrid heating

“…As the amount of additive sulfur is 20 at%, the phase assemblage of sample consists of small amounts of un-reacted graphite, TiC, and other impurities. It is noted that the content of the impurities significantly decreases when compared with that of the sample of 3Ti/2C/1TiS 2 (Fig. 3).…”

“…M n+1 AX n phases (where n = 1, 2, 3, M is an early transition metal, A is a IIIA or IVA element, and X is C or N, abbreviated as MAX) are lately of higher interest because of their unique properties of ceramics and metals [1][2][3], such as readily machinable but high elastic stiffness, high thermal and electrical conductivity, excellent thermal shock resistance and damage tolerance [4][5][6][7][8][9][10], which are crucial for their potential application.…”

Mo2Ga2C: a new ternary nanolaminated carbide

“…[1][2][3] There are approximately 50 M2AX, or 211, phases, five M3AX2, or 312, phases and a growing number of M4AX3, of 413, phases since that structure was first established in Ti3AlN4. In all cases, the Mn+1AXn unit cells are hexagonal -space group P63/mmc -with two formula units per unit cell.…”

Corrosion behavior of Ti3AlC2 in molten KOH at 700 °C

“…Ti 3 AlC 2 is a member of a group of ternary carbides and nitrides known as MAX phases with more than 70 members [1]. MAX phases are governed by the general formula M n+1 AX n , where n = 1, 2 or 3, M is an early transition metal, A is an A-group element (mostly groups 13 and 14), and X is carbon and/or nitrogen [2].…”