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Nanomechanical and microstructural characterization of a zirconia-toughened alumina composite after aging

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Lopes, A. C. O. ; Coelho, P. G. ; Witek, L. ; Benalcazar Jalkh, E. B. ; Genova, L. A. ; Monteiro, K. N. ; Cesar, P. F. ; Lisboa Filho, P. N. ; Bergamo, E. T. P. ; Ramalho, I. S. ; Bonfante, E. A.
Número total de Autores: 11
Tipo de documento: Artigo Científico
Fonte: CERAMICS INTERNATIONAL; v. 45, n. 7, p. 7-pg., 2019-05-01.
Resumo

This study's objective was to mechanically characterize and validate the synthesis method of a polycrystalline composite comprised of 80% alumina reinforced with 20% translucent zirconia (zirconia-toughened alumina, ZTA) and compare to an experimental translucent zirconia. Experimental ZTA (ZTA ZPEX 80/20) and translucent Y-TZP (ZPEX) green-state disc-shaped specimens were obtained via uniaxial/isostatic ceramic powder pressing technique. The discs were sintered using a predefined protocol after both sides of the discs were polished. The specimens were subjected to nanoindentation testing to acquire their elastic modulus (E) and hardness (H) before and after a simulated low temperature degradation (LTD) challenge. Subsequently, the fabricated discs had their 3D surface topographical (Sa/Sq) parameters assessed via interferometry before and after exposure to a simulated LTD aging protocol. The specimens were evaluated using X-ray diffraction (XRD) to assess the tetragonal-monoclinic phase transformation and via scanning electron microscopy (SEM) to evaluate the homogeneity of the surfaces and distribution of the grains. The apparent density was measured using Archimedes' principle. All of the data were statistically evaluated through repeated measures ANOVA following post-hoc comparisons using the Tukey test (p < 0.05). The XRD patterns indicated a higher increase in the monoclinic peak for ZPEX compared to ZTA ZPEX 80/20 aged. LTD aging did not have an effect on the surface roughness (Sa/Sq) for both groups (p > 0.05). A significant decrease in the E values after the aging protocol was observed for both groups (p < 0.01). While ZTA ZPEX 80/ 20 did not show statistically significant differences in the hardness values after the aging protocol (p = 0.36), ZPEX demonstrated a significant decrease in the H values (p = 0.03). For ZTA ZPEX 80/20, simulated LTD aging did not affect the tested properties, except for the E values. Although artificial aging did not affect the surface roughness of ZPEX, the E and H values significantly decreased after aging. (AU)

Processo FAPESP: 12/19078-7 - Desenvolvimento e processamento de compósito de Al2O3-ZrO2 para próteses monolíticas CAD/CAM: efeito do envelhecimento na resistência à flexão biaxial
Beneficiário:Estevam Augusto Bonfante
Modalidade de apoio: Auxílio à Pesquisa - Jovens Pesquisadores
Processo FAPESP: 16/18818-8 - EMU concedido no processo 2012/19078-7: ElectroPuls E3000 Linear-Torsion All-Electric dynamic test instrument package
Beneficiário:Estevam Augusto Bonfante
Modalidade de apoio: Auxílio à Pesquisa - Programa Equipamentos Multiusuários
Processo FAPESP: 18/03072-6 - Compósitos experimentais 70%Al2O3-30%ZrO2: caracterização estrutural e da sobrevida antes e após envelhecimento
Beneficiário:Ernesto Byron Benalcazar Jalkh
Modalidade de apoio: Bolsas no Brasil - Doutorado
Processo FAPESP: 17/19362-0 - DESENVOLVIMENTO E CARACTERIZAÇÃO MECÂNICA E ÓPTICA DE COMPÓSITO 80% Al2O3 e 20% ZrO2 TRANSLÚCIDA PARA PRÓTESES MONOLÍTICAS CAD/CAM
Beneficiário:Adolfo Coelho de Oliveira Lopes
Modalidade de apoio: Bolsas no Exterior - Estágio de Pesquisa - Mestrado
Processo FAPESP: 16/17793-1 - Desenvolvimento e caracterização mecânica e óptica de compósito 80% Al2O3 e 20% ZrO2 translúcida para próteses monolíticas CAD/CAM
Beneficiário:Adolfo Coelho de Oliveira Lopes
Modalidade de apoio: Bolsas no Brasil - Mestrado