Phase (matter)

Engineering

Materials science

Chromatography

Mineralogy

Coating

Ceramic

Thermal conductivity

Thermal expansion

Apatite

Chemical engineering

Pyrochlore

Organic chemistry

Gehlenite

Calcium silicate

Spark plasma sintering

Composite material

Analytical Chemistry (journal)

Sintering

Chemistry

Thermal barrier coating

Journal of Material Science and Technology

A novel high-entropy material, (Y0.2Gd0.2Er0.2Yb0.2Lu0.2)2Zr2O7 was successfully synthesized by the solid state reaction method and spark plasma sintering, and investigated as a promising thermal barrier coating material. Rare-earth elements were distributed homogeneously in the pyrochlore structure. It was found that the prepared high-entropy ceramic maintains pyrochlore structure at the temperature up to 1600 °C, and it possesses a similar thermal expansion coefficient (10.2 × 10−6 K−1 at 25–900 °C) to that of YSZ, low thermal conductivity (< 0.9 W m−1 K−1 at 100–1000 °C) and good CMAS resistance (infiltration depth is 22 μm after annealed at 1300 °C for 24 h). The corrosion process was investigated, and RE elements distributing homogeneously in (Y0.2Gd0.2Er0.2Yb0.2Lu0.2)2Zr2O7 show different diffusion rates in CMAS. RE3+ with a larger radius (closer to Ca2+) is easier to react with CMAS to form an apatite phase.

Calcium-magnesium-alumina-silicate (CMAS) resistant high entropy ceramic (Y0.2Gd0.2Er0.2Yb0.2Lu0.2)2Zr2O7 for thermal barrier coatings