Compressibility and sinterability of Al2O3–YAG nanocomposite powder synthesized by an aqueous sol–gel method

In the present work, the compressibility and sinterability of Al2O3–YAG nanocomposite powder prepared by an aqueous sol–gel method have been investigated. An amorphous nanopowder was synthesized, and it was crystallized to Al2O3–YAG, with an average particle crystallite size of 50 nm, after heat-treatment via a solid-state reaction. It was shown that the compressibility curve of this powder is characterized by two linear parts at low and middle pressures. The agglomeration strength of the powder was about 142 MPa. The densification of composites started at 1000 °C. The relative density and grain size of sintered Al2O3–0.75 mol Y2O3 were measured to be 96% and 650 nm at 1500 °C, respectively. TEM results showed a sub-micronic/nano microstructure is formed. The amount of Y2O3 had a strong effect on the sintering behavior and final microstructure of nanocomposite powders and it inhibited alumina grain growth and suppressed densification process.

Research highlights▶ As it is known, powders synthesized by different methods have different compressibility and sinterability. ▶ In the present work, sinterability and compressibility of Al2O3–YAG nanocomposite powder synthesized by a non-expensive aqueous sol–gel method were investigated. ▶ The row materials for synthesizing of this powder were Al, AlCl3 and Y2O3. ▶ There is no report about the compressibility and sinterability of this powder in the literature. ▶ An amorphous nanopowder was synthesized, and it was crystallized to Al2O3–YAG, with an average particle crystallite size of 50 nm, after heat-treatment via a solid-state reaction. ▶ It was shown that the compressibility curve of this powder is characterized by two linear parts at low and middle pressures. ▶ The agglomeration strength of the powder was about 142 MPa. ▶ The densification of composites started at 1000 °C. ▶ The relative density and grain size of sintered Al2O3–0.75 mol Y2O3 were measured to be 96% and 650 nm at 1500 °C, respectively. ▶ TEM results showed a sub-micronic/nano microstructure is formed. ▶ The amount of Y2O3 had a strong effect on the sintering behavior and final microstructure of nanocomposite powders and it inhibited alumina grain growth and suppressed densification process.