Microstructural evolution of the al2o3-zro2 composite and its correlation with electrical conductivity

Abstract

The Al2O3-ZrO2 composite was studied by impedance spectroscopy, a non destructive technique that was found to be sensitive to the composite's microstructure. The observed decrease in the zirconia grain and grain boundary conductivities points to compression on zirconia grain by alumina matrix. This effect increased with decreased concentration of zirconia in the composite. Measurements were taken of composites above the percolation threshold for vacancy conduction along the zirconia grains. The effect of densification and grain growth on the composite's conduction was measured. The changes in the zirconia grain and grain boundary specific conductivities were found to be correlated

Fracture resistance behavior of alumina–zirconia composites

“…Alumina-zirconia composites, developed by introduction of fine ZrO 2 particles in the alumina matrix, has extensive structural application due to their excellent mechanical properties. Through a suitable adjustment of the concentration of its components, this ceramic composite can offer high level of strength properties, toughness and hardness [1]. Pure alumina ceramics exhibit high hardness and good strength properties but poor toughness, while tetragonal zirconia has high strength properties, high toughness and lower hardness.…”

The influence of the method of addition of Al2O3 to 3YSZ material on its thermal and electrical properties

“…The dense composite system Al 2 O 3 -YSZ is well-known, and the correlation of their microstructure with electrical conductivity was studied earlier [14]. Authors found the correlation between volume fraction of ZrO 2 and Al 2 O 3 and conductivity of composite.…”

Síntesis de nanocomposites NTC-13%ZrO₂ – (87-x)Al₂O₃-xFe

“…Los métodos más utilizados son: reacción en estado sólido, mecanosíntesis, combustión y coprecipitación . Varios autores han utilizado como precursores a los óxidos metálicos correspondientes en tamaños micrométricos, posteriormente los someten a un tiempo de molienda que oscila entre 8 y 24 h empleando bolas de alúmina como medios de molienda (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14). Pocos son los trabajos que han aplicado los métodos de coprecipitación y combustión (15,16); sin embargo, ambos métodos de síntesis requieren de un tratamiento térmico a temperaturas superiores o iguales a 1100 °C a fin de obtener las fases alfa-alúmina y zirconia tetragonal, existiendo diferencia Mediante una síntesis por combustión ureica-nitratos, calcinación y la aplicación de un tratamiento de deposición química catalítica de vapor (CCVD) en una atmósfera H 2 -CH 4 , se obtuvieron polvos nanocomposites: nanotubos de carbono (NTC) en una matriz cerámica -Fe, NTC-13 %ZrO 2 -(87-x)Al 2 O 3 -xFe, (x = 1.9, 4.6 y 6.4 %).…”