Effect of temperature and holding time on the densification of alumina obtained by two-step sintering

Lóh, N.J.; Simão, Lisandro; Jiusti, Jeanini; Noni, Agenor De; Montedo, Oscar Rubem Klegues

doi:10.1016/j.ceramint.2017.03.159

Cited by 52 publications

(24 citation statements)

References 29 publications

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“…ZrO 2 –Al 2 O 3 nanocomposites are often obtained by the sintering of compactified powders [11,26,27,28,29]. The microstructure of a ceramic depends upon the structure of the initial materials used for its synthesis, the dopant distribution used, the heating rate, and the sintering mechanism used.…”

Section: Introductionmentioning

confidence: 99%

“…The density of composite decreased and the open porosity of the ceramic materials grew with increasing amount of Al 2 O 3 . Several studies have manufactured dense ceramics while maintaining a small grain size; most of them used optimized sintering strategies or advanced sintering techniques [11,26,31]. Numerous analyses of the mechanical properties of Al 2 O 3 –ZrO 2 composite systems have also been reported upon [32,33,34,35,36,37], and a wide range of results have been presented.…”

Section: Introductionmentioning

confidence: 99%

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Mechanism of Reduced Sintering Temperature of Al2O3–ZrO2 Nanocomposites Obtained by Microwave Hydrothermal Synthesis

et al. 2018

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A novel method to obtain Al2O3–ZrO2 nanocomposites is presented. It consists of the co-precipitation step of boehmite (AlO(OH)) and ZrO2, followed by microwave hydrothermal treatment at 270 °C and 60 MPa, and by calcination at 600 °C. Using this method, we obtained two nanocomposites: Al2O3–20 wt % ZrO2 and Al2O3–40 wt % ZrO2. Nanocomposites were characterized by Fourier transformed infrared spectroscopy, Raman spectroscopy, X-ray diffraction, and transmission electron microscopy. Sintering behavior and thermal expansion coefficients were investigated during dilatometric tests. The sintering temperatures of the nanocomposites were 1209 °C and 1231 °C, respectively—approximately 100 °C lower than reported for such composites. We attribute the decrease of the sintering temperature to the specific nanostructure obtained using microwave hydrothermal treatment instead of conventional calcination. Microwave hydrothermal treatment resulted in a fine distribution of intermixed highly crystalline nanoparticles of boehmite and zirconia. Such intermixing prevented particle growth, which is a factor reducing sintering temperature. Further, due to reduced grain growth, stability of the θ-Al2O3 phase was extended up to 1200 °C, which enhances the sintering process as well. For the Al2O3–20 wt % ZrO2 composition, we observed stability of the zirconia tetragonal phase up to 1400 °C. We associate this stability with the mutual separation of zirconia nanoparticles in the alumina matrix.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Mechanism of Reduced Sintering Temperature of Al2O3–ZrO2 Nanocomposites Obtained by Microwave Hydrothermal Synthesis

et al. 2018

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“…Bodišová et al 37 observed that, for submicrometric Al 2 O 3 , the critical density would be approximately 92%TD. Lóh et al 22 used the density of 83%TD to determine the T 1 values for commercial Al 2 O 3 . Chinelatto et al 24 studied some TSS sintering curves in Al 2 O 3 nanocomposites with 5 vol% of ZrO 2 nanometric inclusions.…”

Section: Resultsmentioning

confidence: 99%

Microstructure and mechanical properties of Al₂O₃/ZrO₂ composites by two‐step sintering

Ojaimi

Ferreira

Chinelatto

et al. 2020

Int J Applied Ceramic Tech

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Composites of Al2O3/ZrO2 (containing 25, 50, and 75 vol% ZrO2) were prepared by mixing Al2O3 and ZrO2 suspensions. The microstructural control via two‐step sintering (TSS) was the main objective of this work. For this purpose, different sintering curves were constructed, aiming to achieve the best temperature combination for the sintering steps that provides higher density and finer microstructure. The results were compared with single‐step sintering (SSS). Furthermore, microhardness and fracture toughness were measured for the best TSS specimens under each composition. The results showed that the high densities were obtained, and the reduction of grain size was greater than 40% for two‐step sintered specimens, compared to SSS ones. Consequently, microhardness values increased. However, fracture toughness values remained unchanged.

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“…For Al 2 O 3 fabrication, the usual sintering temperature of alumina must be above 1400 C, which requires high energy consumption and is a wasteful process. 26,27 This is not unexpected because Al 2 O 3 has a very high melting point (2072 C), and the atomic movement to ll the particle gaps is very limited at low temperature. 28,29 Being a high temperature process, the energy consumption is very high and the instrumentation, such as a high-temperature furnace, is expensive.…”

Section: Introductionmentioning

confidence: 94%

Fabrication of a ceramic/metal (Al₂O₃/Al) composite by 3D printing as an advanced refractory with enhanced electrical conductivity

Prathumwan

Subannajui

2020

RSC Adv.

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Effect of temperature and holding time on the densification of alumina obtained by two-step sintering

Cited by 52 publications

References 29 publications

Mechanism of Reduced Sintering Temperature of Al2O3–ZrO2 Nanocomposites Obtained by Microwave Hydrothermal Synthesis

Mechanism of Reduced Sintering Temperature of Al2O3–ZrO2 Nanocomposites Obtained by Microwave Hydrothermal Synthesis

Microstructure and mechanical properties of Al₂O₃/ZrO₂ composites by two‐step sintering

Fabrication of a ceramic/metal (Al₂O₃/Al) composite by 3D printing as an advanced refractory with enhanced electrical conductivity

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Effect of temperature and holding time on the densification of alumina obtained by two-step sintering

Cited by 52 publications

References 29 publications

Mechanism of Reduced Sintering Temperature of Al2O3–ZrO2 Nanocomposites Obtained by Microwave Hydrothermal Synthesis

Mechanism of Reduced Sintering Temperature of Al2O3–ZrO2 Nanocomposites Obtained by Microwave Hydrothermal Synthesis

Microstructure and mechanical properties of Al2O3/ZrO2 composites by two‐step sintering

Fabrication of a ceramic/metal (Al2O3/Al) composite by 3D printing as an advanced refractory with enhanced electrical conductivity

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Product

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Microstructure and mechanical properties of Al₂O₃/ZrO₂ composites by two‐step sintering

Fabrication of a ceramic/metal (Al₂O₃/Al) composite by 3D printing as an advanced refractory with enhanced electrical conductivity