Replenishing the oxidation-induced Al-depletion in Cr2AlC MAX phase coatings
Abstract
A C T Cr 2 AlC MAX phase coatings are known to form a protective alumina scale upon high temperature oxidation. Scale formation causes Al depletion, which results in the formation of Cr-carbides and pores that, in turn, cause coating failure. Here, we show that the oxidation-driven Al depletion of the coating is prevented by Alreplenishment using an Al-reservoir (Al-containing substrate), thereby extending the coating lifetime. Cr 2 AlC substrates with coarse and fine grain distributions were produced by spark plasma sintering and coated with Cr 2 AlC by magnetron sputtering. Upon oxidation at 1100 • C the Cr 2 AlC coatings, deposited onto a coarse-grained reservoir and onto MgO without an Al-reservoir, showed no significant change in Al content of the coating postoxidation, and hence no evidence for Al-replenishment from the substrate. However, in the case of a Cr 2 AlC coating deposited onto a fine-grained substrate, the Al content of the coating post-oxidation remained close to the initial concentration (~23 at.%). This replenishment is rationalized by the presence of more grain boundaries in the fine-grained substrate, versus the coarse-grained one, enabling sufficient Al diffusion across the substrate/ coating interface to offset the Al losses to the scale.
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BibTeX
@article{azina2026replenishing,
title = {{Replenishing the oxidation-induced Al-depletion in Cr2AlC MAX phase coatings}},
author = {Clio Azina and Devi Janani Ramesh and Marcus Hans and Per Eklund and Jesus Gonzalez-Julian and Jochen M Schneider},
journal = {Materials \& Design},
year = {2026},
month = may,
doi = {10.1016/j.matdes.2026.116316},
url = {https://hal.science/hal-05796808v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Replenishing the oxidation-induced Al-depletion in Cr2AlC MAX phase coatings
AU - Clio Azina
AU - Devi Janani Ramesh
AU - Marcus Hans
AU - Per Eklund
AU - Jesus Gonzalez-Julian
AU - Jochen M Schneider
PY - 2026
DA - 2026/05/28
JO - Materials & Design
DO - 10.1016/j.matdes.2026.116316
UR - https://hal.science/hal-05796808v1
AB - A C T Cr 2 AlC MAX phase coatings are known to form a protective alumina scale upon high temperature oxidation. Scale formation causes Al depletion, which results in the formation of Cr-carbides and pores that, in turn, cause coating failure. Here, we show that the oxidation-driven Al depletion of the coating is prevented by Alreplenishment using an Al-reservoir (Al-containing substrate), thereby extending the coating lifetime. Cr 2 AlC substrates with coarse and fine grain distributions were produced by spark plasma sintering and coated with Cr 2 AlC by magnetron sputtering. Upon oxidation at 1100 • C the Cr 2 AlC coatings, deposited onto a coarse-grained reservoir and onto MgO without an Al-reservoir, showed no significant change in Al content of the coating postoxidation, and hence no evidence for Al-replenishment from the substrate. However, in the case of a Cr 2 AlC coating deposited onto a fine-grained substrate, the Al content of the coating post-oxidation remained close to the initial concentration (~23 at.%). This replenishment is rationalized by the presence of more grain boundaries in the fine-grained substrate, versus the coarse-grained one, enabling sufficient Al diffusion across the substrate/ coating interface to offset the Al losses to the scale.
SN - 0261-3069
SN - 0264-1275
ER -