Alpha-Alumina/Tetragonal Zirconia Composites Modified with Strontium Cations

• Published in: Inorganic materials 2023-06, Vol.59 (6), p.668-676
• Main Authors: Podzorova, L. I., Il’icheva, A. A., Pen’kova, O. I., Sirotinkin, V. P., Antonova, O. S., Kaplan, M. A., Frolova, M. G.
• Format: Article
• Language: English
• Subjects: Aluminum oxide; Bend strength; Chemistry; Chemistry and Materials Science; Composite materials; Industrial Chemistry/Chemical Engineering; Inorganic Chemistry; Materials Science; Mechanical properties; Phase composition; Polycrystals; Sintering (powder metallurgy); Sol-gel processes; Tetragonal zirconia; Tetragonal zirconia polycrystals
• ISSN: 0020-1685; 1608-3172
• DOI: 10.1134/S0020168523060122

— Composites have been prepared using nanopowders whose precursors were synthesized by a sol–gel hydrolysis process in 1 M solutions of the ZrOCl 2 , Al(NO 3 ) 3 , Yb(NO 3 ) 3 , and Sr (NO 3 ) 2 salts the amount of which corresponded to the basic composition (mol %) 50Al 2 O 3 , (50 – n )3Yb-TZP (tetragonal zirconia polycrystals stabilized with 3% Yb 2 O 3 ), and n = 1, 3, or 6% SrO as a modifier. We have studied how the amount of the modifier influences the phase composition, microstructure, and mechanical properties of the composites. The addition of the modifier has been found to shift the θ-Al 2 O 3 → α-Al 2 O 3 transition to higher temperatures. In situ sintering of the starting nanopowders in the temperature range 1250–1400°C has been shown to result in the formation of alpha-alumina and strontium hexaaluminate. Raising the modifier concentration to above 3% increases the closed porosity of the composites, reducing their bending strength from 700 to 450 MPs.