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Synthesis, sintering, and effect of surface roughness on oxidation of submicron Ti 2 AlC ceramics
Author(s) -
Badie Sylvain,
Dash Apurv,
Sohn Yoo Jung,
Vaßen Robert,
Guillon Olivier,
GonzalezJulian Jesus
Publication year - 2021
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.17582
Subject(s) - materials science , sintering , relative density , spark plasma sintering , microstructure , surface roughness , rutile , ceramic , oxide , phase (matter) , surface finish , titanium , composite material , metallurgy , chemical engineering , chemistry , organic chemistry , engineering
Submicron Ti 2 AlC MAX phase powder was synthesized by molten salt shielded synthesis (MS 3 ) using a Ti:Al:C molar ratio of 2:1:0.9 at a process temperature of 1000°C for 5 hours. The synthesized powder presented a mean particle size of ~0.9 µm and a purity of 91 wt. % Ti 2 AlC, containing 6 wt. % Ti 3 AlC 2 . The Ti 2 AlC powder was sintered by pressureless sintering, achieving a maximal relative density of 90%, hence field‐assisted sintering technology/spark plasma sintering was used to enhance densification. The fine‐grained microstructure was preserved, and phase purity of Ti 2 AlC was unaltered in the latter case, with a relative density of 98.5%. Oxidation was performed at 1200°C for 50 hours in static air of dense monolithic Ti 2 AlC with different surface finish, (polished, ground and sandblasted) which resulted in the formation of an approx. 8 µm thin aluminum oxide (Al 2 O 3 ) layer decorated with titanium dioxide (rutile, TiO 2 ) colonies. Surface quality had no influence on Al 2 O 3 scale thickness, but the amount and size of TiO 2 crystals increased with surface roughness. A phenomenon of rumpling of the thermally grown oxide (TGO) was observed and a model to estimate the extent of deformation is proposed.