Influence of heat treatment temperature on the properties of the lithium disilicate‐fluorcanasite glass‐ceramics

Glass composition 39PbO–1BaO–25TiO2–9.8Al2O3–24.2SiO2–1B2O3 (mol%) crystallized on heat treatment at ≥600 °C to form glass-ceramics whose majority phase was PbTiO3 (PT). At 600 °C, nano-size PT crystals (∼20–50 nm) with a c/a ratio of 1.000(1) were observed, but as heat-treatment temperature increased to 1000 °C, the crystal size and c/a ratio increased to ∼1.2 μm and 1.056(4), respectively. Permittivity measurements as a function of temperature revealed a broad peak at ∼400 °C associated with the nanocrystalline PT crystals, but it sharpened and increased in temperature as heat treatment temperature increased to 1000 °C. The causes of peak broadening and shift of Tc are believed to be due to either clamping of PT crystals by glass matrix, finite size effects due to their intrinsically small size, or the incorporation of dopant impurities such as Al, Si, or Ba ions in the PT phase.

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Effect of heat treatment temperature to the crystal growth and optical performance of Mn3O4 doped α-Zn2SiO4 based glass-ceramics

Results in Physics ◽

10.1016/j.rinp.2019.102569 ◽

2019 ◽

Vol 15 ◽

pp. 102569

Author(s):

Mohd Hafiz Mohd Zaid ◽

Khamirul Amin Matori ◽

Sidek Hj Ab Aziz ◽

Halimah Mohamed Kamari ◽

Yap Wing Fen ◽

...

Keyword(s):

Heat Treatment ◽

Crystal Growth ◽

Heat Treatment Temperature ◽

Glass Ceramics ◽

Treatment Temperature ◽

Optical Performance

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BISMUTH NIOBATE-BASED GLASS-CERAMICS FOR DIELECTRICALLY LOADED MICROWAVE ANTENNAS

Functional Materials Letters ◽

10.1142/s179360470800006x ◽

2008 ◽

Vol 01 (01) ◽

pp. 25-30 ◽

Cited By ~ 15

Author(s):

MEHDI MIRSANEH ◽

BEATA ZALINSKA ◽

OLIVER P. LEISTEN ◽

IAN M. REANEY

Keyword(s):

Heat Treatment ◽

Resonant Frequency ◽

Glass Ceramic ◽

Heat Treatment Temperature ◽

Glass Ceramics ◽

Treatment Temperature ◽

Ceramic Processing ◽

Ceramic System ◽

Microwave Antennas ◽

Microwave Applications

A castable, low melting temperature glass-ceramic system (30% Bi 2 O 3, 30% Nb 2 O 5, 30% B 2 O 3 and 10% SiO 2, in mol%) suitable for microwave applications is fabricated and characterized. Depending on heat treatment temperature, the glass ceramic exhibits permittivity, 15 ≤ ε r ≤ 41, temperature coefficient of resonant frequency of -160 ≤ τ f ≤ +100 MK -1 and microwave quality factor of 300 GHz ≤ Qf ≤ 15000 GHz . The highest Qf occurs at 960°C heat treatment with ε r = 15, τ f = -80 MK -1 and Qf = 15000 GHz . Applications are envisaged such as castable dielectrically-loaded antenna pucks, removing the need for complex ceramic processing.

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Influence of Heat Treatment Conditions on Crystallization and Thermal Expansion of Las Glass-Ceramics

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.168-170.1712 ◽

2010 ◽

Vol 168-170 ◽

pp. 1712-1716

Author(s):

Zhuo Hao Xiao ◽

Ming Hua Luo

Keyword(s):

Heat Treatment ◽

Thermal Expansion ◽

Heat Treatment Temperature ◽

Glass Ceramics ◽

Treatment Temperature ◽

Matrix Glass ◽

Treatment Conditions ◽

The Matrix ◽

Crystal Phases ◽

Quenching Method

The LAS glass containing P2O5has been prepared by conventional molten quenching method. The influence of heat treatment conditions on crystallization behavior, including phase transformation and microstructure, and thermal expansion coefficient (TEC) of Li2O–Al2O3–SiO2(LAS) glass-ceramics were investigated. DSC, XRD, SEM and TEC were used to detect the microstructure and properties of glass-ceramics under the different heat-treatment conditions. The results show the virgilite crystalline separated firstly from the matrix glass when heat treatment temperature was 850 °C. As the heat treatment temperature increased from 850 °C to 1050 °C, virgilite and β-spodumene were identified as main crystal phases. The TEC of glass-ceramics ranges from 0.5×10-6 °C-1to 2.8×10-6 °C-1, which is much lower than that of matrix glass.

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Sintering and Crystallization of Glass-Ceramics for Optical Fiber Ferrule

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.336-338.1840 ◽

2007 ◽

Vol 336-338 ◽

pp. 1840-1842

Author(s):

Y.M. Zhu ◽

Xia Wan Wu ◽

Zhi Hong Li

Keyword(s):

Heat Treatment ◽

Heat Treatment Temperature ◽

Glass Powder ◽

Treatment Time ◽

Glass Ceramics ◽

Treatment Temperature ◽

Residual Glass ◽

Sio2 Glass ◽

Powder Compacts ◽

Crystallization Of Glass

The crystallization and sintering of the Li2O-Al2O3-SiO2 glass powder compacts were studied. Results showed the relative densities of the sintered compacts with lower crystallization temperatures were higher than those with higher crystallization temperatures. A small amount of residual glass in the crystallized compact was good for sintering and densification. Compared with the heat treatment time, the heat treatment temperature was an important factor for the crystallization and sintering of glass powder compacts. The crystallized compacts with a small amount of residual glass should be sintered at a relatively higher heating rate under the prerequisite of keeping sintered compacts from deformation.

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Preparation and Characterization of β-Eucryptite Glass Ceramics

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.624.134 ◽

2012 ◽

Vol 624 ◽

pp. 134-137 ◽

Cited By ~ 1

Author(s):

Ping Zhai ◽

Xiao Feng Duan ◽

Da Qian Chen ◽

Chong Hai Wang

Keyword(s):

Heat Treatment ◽

Expansion Coefficient ◽

Heat Treatment Temperature ◽

Glass Ceramics ◽

Treatment Temperature ◽

Structure And Properties ◽

X Ray Diffraction ◽

Solid Reaction ◽

X Ray

In this paper, β-eucryptite glass ceramics were synthesized by using solid reaction method. Phase constitution, structure and properties of the material were studied by X-ray diffraction (XRD) and differential thermal analysis (DTA). Furthermore, the effects of heat treatment temperature and preservation time on the thermal expansion coefficient were also analyzed. The results showed that the crystallization temperature of β-eucryptite glass ceramics was in the range of 810-860 °C and the content was more than 90%. With the increase of heat treatment temperature, the material expansion coefficient decreased.

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Effect of NaNbO3 Crystalline Aggregates on the Electrical Properties of SiO2-Na2O-Nb2O5 Glass-Ceramics

Materials Science Forum ◽

10.4028/www.scientific.net/msf.514-516.274 ◽

2006 ◽

Vol 514-516 ◽

pp. 274-279 ◽

Cited By ~ 1

Author(s):

Manuel P.F. Graça ◽

Maria Gracinda Ferreira da Silva ◽

Manuel A. Valente

Keyword(s):

Heat Treatment ◽

Electrical Properties ◽

Heat Treatment Temperature ◽

Glass Ceramics ◽

Treatment Temperature ◽

Treated Sample ◽

Dc And Ac Conductivity ◽

Potential Applications ◽

Quenching Method ◽

Crystalline Aggregates

The presence of NaNbO3 crystallites in a glass matrix has scientific and technological interest due to their electrical properties and potential applications in microwave, pyroelectric and piezoelectric devices. A glass with the composition 60SiO2-30Na2O-10Nb2O5 (% mole) was prepared by the melt-quenching method. NaNbO3 microcrystallites were precipitated on the surface of the glass by heat-treatment. Scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy, dc and ac conductivity measurements were used in the study of the glass and glassceramic materials. The number of particles, precipitated in the surface of the glass-ceramic samples, increases from the 650 to the 750°C and decrease in the 800°C sample. In all these samples the particles size thickness increases with the rise of the heat-treatment temperature. In the 750 and 800°C samples it was observed the presence of a white surface layer formed by NaNbO3 crystallites aggregations. The dc conductivity (σdc) decreases with the rise of the heat –treatment temperature up to 750°C and the dielectric constant value, at 1kHz and room temperature, has a maximum value of 34.94 for the 800 °C treated sample.

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