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

A. C.O. Lopes; P. G. Coelho; L. Witek; E. B. Benalcázar Jalkh; L. A. Gênova; K. N. Monteiro; P. F. Cesar; P. N. Lisboa Filho; E. T.P. Bergamo; I. S. Ramalho; E. A. Bonfante

doi:10.1016/j.ceramint.2019.01.211

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

A. C.O. Lopes, P. G. Coelho, L. Witek, E. B. Benalcázar Jalkh, L. A. Gênova, K. N. Monteiro, P. F. Cesar, P. N. Lisboa Filho, E. T.P. Bergamo, I. S. Ramalho, E. A. Bonfante

Research output: Contribution to journal › Article › peer-review

Abstract

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.

Original language	English (US)
Pages (from-to)	8840-8846
Number of pages	7
Journal	Ceramics International
Volume	45
Issue number	7
DOIs	https://doi.org/10.1016/j.ceramint.2019.01.211
State	Published - May 2019

Keywords

Composites
Mechanical properties
Microstructure
ZrO –Al O

ASJC Scopus subject areas

Electronic, Optical and Magnetic Materials
Ceramics and Composites
Process Chemistry and Technology
Surfaces, Coatings and Films
Materials Chemistry

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10.1016/j.ceramint.2019.01.211

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Lopes, A. C. O., Coelho, P. G., Witek, L., Benalcázar Jalkh, E. B., Gênova, L. A., Monteiro, K. N., Cesar, P. F., Lisboa Filho, P. N., Bergamo, E. T. P., Ramalho, I. S., & Bonfante, E. A. (2019). Nanomechanical and microstructural characterization of a zirconia-toughened alumina composite after aging. Ceramics International, 45(7), 8840-8846. https://doi.org/10.1016/j.ceramint.2019.01.211

Lopes, ACO, Coelho, PG, Witek, L, Benalcázar Jalkh, EB, Gênova, LA, Monteiro, KN, Cesar, PF, Lisboa Filho, PN, Bergamo, ETP, Ramalho, IS & Bonfante, EA 2019, 'Nanomechanical and microstructural characterization of a zirconia-toughened alumina composite after aging', Ceramics International, vol. 45, no. 7, pp. 8840-8846. https://doi.org/10.1016/j.ceramint.2019.01.211

@article{6e3f458b5a95443ba3ba935f29c789e5,

title = "Nanomechanical and microstructural characterization of a zirconia-toughened alumina composite after aging",

abstract = "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{\textquoteright} 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.",

keywords = "Composites, Mechanical properties, Microstructure, ZrO –Al O",

author = "Lopes, {A. C.O.} and Coelho, {P. G.} and L. Witek and {Benalc{\'a}zar Jalkh}, {E. B.} and G{\^e}nova, {L. A.} and Monteiro, {K. N.} and Cesar, {P. F.} and {Lisboa Filho}, {P. N.} and Bergamo, {E. T.P.} and Ramalho, {I. S.} and Bonfante, {E. A.}",

note = "Funding Information: The authors acknowledge grants from S{\~a}o Paulo Research Foundation (FAPESP) # 2012/19078-7 , #EMU 2016/18818-8 , #2016/17793-1 , #2017/19362-0 , and #2018/03072-6 ; Conselho Nacional de Desenvolvimento Cient{\'i}fico e Tecnol{\'o}gico (CNPq), grants #304589/2017-9 and #434487/2018-0 ; and Coordena{\c c}{\~a}o de Aperfei{\c c}oamento de Pessoal de N{\'i}vel Superior - Brasil (CAPES) - Finance Code 001 . Publisher Copyright: {\textcopyright} 2019",

year = "2019",

month = may,

doi = "10.1016/j.ceramint.2019.01.211",

language = "English (US)",

volume = "45",

pages = "8840--8846",

journal = "Ceramics International",

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number = "7",

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T1 - Nanomechanical and microstructural characterization of a zirconia-toughened alumina composite after aging

AU - Lopes, A. C.O.

AU - Coelho, P. G.

AU - Witek, L.

AU - Benalcázar Jalkh, E. B.

AU - Gênova, L. A.

AU - Monteiro, K. N.

AU - Cesar, P. F.

AU - Lisboa Filho, P. N.

AU - Bergamo, E. T.P.

AU - Ramalho, I. S.

AU - Bonfante, E. A.

N1 - Funding Information: The authors acknowledge grants from São Paulo Research Foundation (FAPESP) # 2012/19078-7 , #EMU 2016/18818-8 , #2016/17793-1 , #2017/19362-0 , and #2018/03072-6 ; Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), grants #304589/2017-9 and #434487/2018-0 ; and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (CAPES) - Finance Code 001 . Publisher Copyright: © 2019

PY - 2019/5

Y1 - 2019/5

N2 - 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.

AB - 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.

KW - Composites

KW - Mechanical properties

KW - Microstructure

KW - ZrO –Al O

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JO - Ceramics International

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

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