Effect of a LZSA glass-ceramic addition on the sintering behavior of alumina

Montedo, Oscar Rubem Klegues; Milak, Pâmela; Minatto, F. D.; Nuernberg, Rafael Bianchini; Faller, Cristian Arnaldo; Oliveira, Antônio Pedro Novaes de; Noni, Agenor De

doi:10.1007/s10973-015-5144-5

Cited by 15 publications

(15 citation statements)

References 27 publications

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“…2 shows the LS behavior of the studied compositions. As it can be seen, the sintering of LZSA glass-ceramic (P) occurred between 600 and 800 °C, as previously reported [25][26][27][28]. However, the addition of alumina nanoparticles increased the sintering start temperature and the sintering range.…”

Section: Resultssupporting

confidence: 69%

“…Composites with 5% nano-sized alumina showed a CTE lower than that of the equivalent formulation with submicrometric alumina. Glass-ceramics produced from the LZSA (Li 2 O-ZrO 2 -SiO 2 -Al 2 O 3 ) glass system have been studied [24][25][26][27][28] since they show low CET and are chemically resistant materials. However, the properties of such glass-ceramics can also be improved by increasing the crystallinity.…”

Section: Introductionmentioning

confidence: 99%

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Solid-state reaction in nanoparticulate alumina/LZSA glass-ceramic composites

2018

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In this work, some properties, such as sinterability, modulus of elasticity (E), coefficient of thermal expansion (CTE) and dielectric constant (ε r ), of composites constituted by nanoparticulate alumina (27-43 nm, 35 m 2 .g -1 ) in different contents (0 to 77 vol%) and a LZSA glass-ceramic composition (17.7Li 2 O-5.2ZrO 2 -68.1SiO 2 -9.0Al 2 O 3 , molar basis) were evaluated. Dry powders of the raw materials (alumina and LZSA parent glass, frit) were uniaxially pressed (40 MPa) and the obtained compacts were sintered at 600-950 °C (1 h holding time). X-ray diffraction (XRD) study was performed in order to investigate the solid-state reactions occurred in LZSA-based compositions during sintering. XRD results were correlated to the CTE, E and ε r of sintered samples. The CTE of the obtained composites decreased as alumina content increased mainly due to the β-spodumene ss (solid solution Li 2 O.Al 2 O 3 .4-10SiO 2 ) formation. The results concerning the E (22.3±1.5 GPa) and ε r (3.1±1.3) for the composite with 5.6 vol% addition sintered at 850 °C for 1 h indicated, in a preliminary way, the possibility of development of materials with suitable properties for applications concerning to the low temperature co-fired ceramic (LTCC) technology.

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Section: Resultssupporting

confidence: 69%

Section: Introductionmentioning

confidence: 99%

Solid-state reaction in nanoparticulate alumina/LZSA glass-ceramic composites

2018

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“…In this Part II, LZSA glass-ceramic was added to alumina to cause suppression of grain growth; however, crystalline phases were formed during heating in the range of 640-820 °C 19 . Because the composites were sintered at higher temperatures (> 1450 °C), those crystalline phases were dissolved into the glassy phase after the melting of the LZSA.…”

Section: Resultsmentioning

confidence: 99%

“…Thus, the use of a glass-such as a glass-ceramic-that encourages sintering during heating and also crystallizes in stable phases during the cooling cycle may be an alternative way to obtain highdensity alumina by LPS, while simultaneously producing a large amount of crystalline phase in the grain boundaries 19 . In addition, less grain growth and less residual glassy phase could be obtained.…”

Section: Introductionmentioning

confidence: 99%

Effect of LZSA Glass-Ceramic Addition on Pressureless Sintered Alumina. Part II: Mechanical Behavior

et al. 2017

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This work aims to evaluate the influence of a Li 2 O-ZrO 2 -SiO 2 -Al 2 O 3 (LZSA) glass-ceramic on the mechanical behavior of alumina. Composites were prepared from alumina with three different particle sizes and 7 to 21 vol% of an LZSA glass-ceramic composition (11.6Li 2 O-16.8ZrO 2 -68.2SiO 2 -3.4Al 2 O 3 ,). Specimens were obtained by uniaxial pressing. The optimum sintering temperature and holding time were found to be different for each composite. Structural characterization (bulk density and crystalline phases); mechanical characterization (flexure strength, elastic modulus, fracture toughness, and fracture energy); and microstructural analyses were carried out. Fine-grained alumina-based composite containing 21 vol% of glass-ceramic (1470 ºC and 3 h holding time, 2.0% porosity) showed a fracture toughness of 4.93 MPa·m 0.5 , an elastic modulus of 210 GPa, a fracture energy of 57 J·m -2 , and a flexural strength of 170 MPa, in very good agreement with values reported by the literature. An increase of 37-177% in the fracture energy due to 21 vol% LZSA addition in the alumina was achieved for the range of grain size obtained in this work. Even though the final composition included a glassy component, the observed mechanical properties confirmed the effectiveness of the crystalline phases that were formed from LZSA glass-ceramic in reducing the propagation of cracks. The results showed that the addition of the LZSA glass-ceramic improved the mechanical properties of alumina.

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“…Avaliações de características como módulo de elasticidade (E) e coeficiente de expansão térmica (CET) são indispensáveis nesta etapa [6]. Neste sentido, vitrocerâmicos do sistema LZSA (Li 2 O-ZrO 2 -SiO 2 -Al 2 O 3 ) se destacam devido à sua microestrutura composta de cristais micrométricos de espodumênio-β ss (solução sólida, Li 2 O.Al 2 O 3 .4-10SiO 2 ) e silicato de zircônio (ZrSiO 4 ), que conferem a este material densificação à baixa temperatura, baixo CET e valores de propriedades mecânicas que o tornam interessante para emprego, por exemplo, em aplicações de LTCC (low temperature co-fired ceramics) obtidos por tape casting [7][8][9][10][11][12][13][14][15].…”

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