Substrate orientation effects on the nucleation and growth of the Mn+1AXn phase Ti2AlC

Abstract

The M n+1 AX n ͑MAX͒ phases are ternary compounds comprising alternating layers of a transition metal carbide or nitride and a third "A-group" element. The effect of substrate orientation on the growth of Ti 2 AlC MAX phase films was investigated by studying pulsed cathodic arc deposited samples grown on sapphire cut along the ͑0001͒, ͑1010͒, and ͑1102͒ crystallographic planes. Characterization of these samples was by x-ray diffraction, atomic force microscopy, and cross-sectional transmission electron microscopy. On the ͑1010͒ substrate, tilted ͑1018͒ growth of Ti 2 AlC was found, such that the TiC octahedra of the MAX phase structure have the same orientation as a spontaneously formed epitaxial TiC sublayer, preserving the typical TiC-Ti 2 AlC epitaxial relationship and confirming the importance of this relationship in determining MAX phase film orientation. An additional component of Ti 2 AlC with tilted fiber texture was observed in this sample; tilted fiber texture, or axiotaxy, has not previously been seen in MAX phase films.

Phase-stabilization and substrate effects on nucleation and growth of (Ti,V)n+1GeCn thin films

“…16 , 20.36 , 30.76 , and 41.38 . These peaks correspond to the 0002, 0004, 0006, and 0008 peaks of (Ti,V) 3 GeC 2 .…”

“…1, 5-9). However, solid solution MAX-phase thin films have been studied much less and offer an important opportunity for exploration, as it is relatively easy to grow MAX phases epitaxially, [10][11][12][13][14][15][16] and thin-film growth permits the study of materials that are metastable and difficult to synthesize in bulk. 2 Among the relatively few studies that exist on MAX-phase solid solutions in thin films, Scabarozi et al reported M-site solid solutions of (Ti,Nb) 2 AlC thin films.…”

Synthesis and characterization of Ti 2 AlC coatings by magnetron sputtering from three elemental targets and ex-situ annealing

“…A separate plasma source was needed to compensate the lost element when deposited from one compound target. Epitaxial single-phase growth of Ti2AlC on α-Al2O3 (001) single crystal has been deposited by pulsed cathodic arc deposition using multi-cathodes at 900°C; substitutional O (residual gas in chamber) in some C lattice sites was observed for the Ti2AlC films [21,39,40]. High velocity oxy-fuel spray [24,41,42] and cold spray processed [8,25] were also adopted to deposit thick Ti2AlC coating as oxidation resistant coating from Ti2AlC powders.…”

Compositional dependence of epitaxial Tin+1SiCn MAX-phase thin films grown from a Ti3SiC2 compound target

“…From HRTEM, we find no MAX-phase nucleation directly formed on the surface of Al 2 O 3 substrate, which is different from previous studies on Ti 3 AlC 2 . [60][61][62][63] Instead, TiC is nucleated on the Al 2 O 3 substrate with an epitaxial relationship of (111)[11 2]TiC==(0002)½1 100]Al 2 O 3 as shown in Fig. 6(b).…”