Effect of Heat Treatment Time on Properties of Mica-Based Glass-Ceramics for Restorative Dental Materials

2016 ◽  
Vol 702 ◽  
pp. 23-27 ◽  
Author(s):  
Thapanee Srichumpong ◽  
Kallaya Suputtamongkol ◽  
Warat Chinpanuwat ◽  
Pronbadin Nampachoke ◽  
Jia Bai ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Crystal Size ◽  
Treatment Time ◽  
Dental Materials ◽  
Glass Ceramics ◽  
Nucleation Time ◽  
Human Enamel ◽  
Restorative Dental Materials ◽  
Dental Applications ◽  
Stage Heat Treatment

The objective of this research is to focus improving the properties of machinable mica-based glass-ceramics in order for restorative dental materials. The glass-ceramics derived from the SiO2- Al2O3-MgO-MgF2-SrCO3-CaCO3-CaF2-P2O5 system were produced by a two-stage heat treatment. It was elucidated that the optimum nucleation and the crystallization temperatures were at 643°C and 892°C. The various heat treatment times in the first stage were applied as 3, 6, 12, 24, 48 and 72 h, respectively, on the optimum nucleation temperature to produce mica-based glass-ceramics. XRD results showed that specimens of variety of nucleation time had similar crystalline structures such as calcium-mica, fluorapatite, stishovite, anorthite, strontiumapatite and forsterite phases. The microstructures of glass-ceramics were observed by SEM basically as interlocked plate-like and needle-like microstructures of mica and fluorapatite, respectively, in all specimens. Furthermore, different heat treatment times influenced on the revealed crystal size of the glass-ceramics; the longer heat treatment, the smaller crystals. The resultant glass-ceramics gave the results of biaxial flexural strength (178-224 MPa) and Vickers hardness (295-393 HV) increasing with the formation of the interconnected mica phases which contributed to improve the machinability. The values of the properties were comparable to those of human enamel and suitable for some restorative dental applications.

Crystallization and dielectric properties of SrO–BaO–Nb2O5–GeO2 tungsten–bronze glass–ceramics

2001 ◽  
Vol 16 (7) ◽  
pp. 2057-2063 ◽  
Author(s):  
Jiin-Jyh Shyu ◽  
Hsin-Wei Peng
Keyword(s):  
Heat Treatment ◽  
Dielectric Properties ◽  
Tungsten Bronze ◽  
Glass Ceramics ◽  
Dielectric Behavior ◽  
Dendritic Morphology ◽  
Dielectric Constants ◽  
Two Stage ◽  
Tetragonal Tungsten Bronze ◽  
Stage Heat Treatment

The crystallization and dielectric properties of SrO–BaO–Nb2O5–GeO2 glass–ceramics were investigated. One- and two-stage heat-treatment methods were used to convert the parent glass to glass–ceramics. Strontium barium niobate (SBN) with a tetragonal tungsten-bronze structure formed as the major crystalline phase. When the crystallizing temperature/time was increased, the secondary crystalline BaGe2O5 phase coexisted with SBN. BaGe2O5 formed as a surface layer grown from the surface into the interior of the sample. The dendritic morphology of SBN crystals was examined. The glass–ceramics crystallized by two-stage heat treatment have higher dielectric constants than those crystallized by one-stage heat treatment. The highest dielectric constant that was obtained in the present glass–ceramics was 320. The glass–ceramics showed relaxor-type dielectric behavior.

Lead titanate glass-ceramics derived from a silicate-based melt

2005 ◽  
Vol 20 (5) ◽  
pp. 1316-1323 ◽  
Author(s):  
P. Sooksaen ◽  
I.M. Reaney ◽  
D.C. Sinclair
Keyword(s):  
Heat Treatment ◽  
Heat Treatment Temperature ◽  
Crystal Size ◽  
Finite Size ◽  
Glass Ceramics ◽  
Treatment Temperature ◽  
Finite Size Effects ◽  
Peak Broadening ◽  
Permittivity Measurements ◽  
Nano Size

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.

scholarly journals Fracture toughness of experimental mica-based glass-ceramics and four commercial glass-ceramics restorative dental materials

2019 ◽  
Vol 38 (3) ◽  
pp. 378-387 ◽  
Author(s):  
Thapanee SRICHUMPONG ◽  
Pimnida PHOKHINCHATCHANAN ◽  
Noparat THONGPUN ◽  
Duangrudee CHAYSUWAN ◽  
Kallaya SUPUTTAMONGKOL
Keyword(s):  
Fracture Toughness ◽  
Dental Materials ◽  
Glass Ceramics ◽  
Commercial Glass ◽  
Restorative Dental Materials

Formation of NaNbO3 Crystals in Dielectric Glass and Glass-Ceramics of a Na2O-Nb2O5-Al2O3-SiO2 System

2008 ◽  
Vol 55-57 ◽  
pp. 229-232 ◽  
Author(s):  
S. Thongsaeng ◽  
Anuson Niyompan ◽  
Rungnapa Tipakontitikul ◽  
Kamonpan Pengpat
Keyword(s):  
Heat Treatment ◽  
Treatment Time ◽  
Glass Ceramics ◽  
Glass Production ◽  
Nucleating Agent ◽  
Aluminum Silicate ◽  
Phase Identification ◽  
Dielectric Glass ◽  
Xrd Patterns ◽  
Glass Compositions

Dielectric glass and glass-ceramics were derived from Na2O-Nb2O5-Al2O3-SiO2 system. Small amount of TiO2 were also introduced into glass compositions to study crystallization behavior of the glass with present of this nucleating agent. Conventional melt-quenching technique was employed for a glass production and the selected bulk glass samples were subjected to the heat-treatment process at appropriate temperature. After six different glass compositions were produced, and by observation with necked eyes, all obtained glass samples are in light brown color and some samples were opaque due to crystallization took place during quenching. Phase identification through XRD patterns show that there were 3 phases, NaNbO3, NaNbO8 and a sodium aluminum silicate compound, found in those opaque glass samples. NaNbO3 is a predominant phase in all samples. Fortunately, clear transparent glass was obtained from the composition with no TiO2 addition. Heat treatment of this glass did not induce phase change, three aforementioned phases still present. Increasing heat treatment time promoted a higher of observed intensity of NaNbO3. But the NaNbO3 crystalline size was not significantly developed with time. The dielectric response of the NaNbO3 crystals in the glass-ceramics samples are influenced by presence of other crystalline phases.

Effect of Heat Treatment Conditions on Microstructure and Infrared Transmission Property of Germanate Oxyfluoride Glass-Ceramics

2010 ◽  
Vol 663-665 ◽  
pp. 1285-1288
Author(s):  
Zhuo Hao Xiao ◽  
Sheng Long Wang
Keyword(s):  
Heat Treatment ◽  
Crystal Size ◽  
Structural Characteristics ◽  
Glass Ceramics ◽  
Infrared Transmission ◽  
Oxyfluoride Glass ◽  
Treatment Conditions ◽  
Ir Transmission ◽  
Temperature Ranges ◽  
Good Transparency

Germanate oxyfluoride glass in CaF2/BaF2-AlF3-SiO2-GeO2 was prepared by melt quenching technique and subsequently converted to glass-ceramics with microstructures comprised nano-crystallites in a residual glass matrix by two-step heat treatments process. DSC, XRD, SEM and IR transmission investigations were used to determine structural characteristics and optical property of the prepared germanate oxyfluoride glass-ceramics. The influences of heat treatment conditions on crystallization behaviors and infrared transmission were discussed. The results show that crystal phase in the glass-ceramics is only Ge2Al6O13 and the crystal size is about 20nm-80nm when treated temperature ranges from 900 oC to 960oC. Good transparency is exhibited in visible light band to midinfrared band (5.0um) when treated temperature is low than 940 oC.

Surface Crystallization of ZnO-Al2O3-SiO2 Glass

2007 ◽  
Vol 280-283 ◽  
pp. 1655-1658
Author(s):  
Xiao Dong Li ◽  
Jie Mo Tian ◽  
Chen Wang ◽  
Li Min Dong
Keyword(s):  
Heat Treatment ◽  
Treatment Time ◽  
Glass Ceramics ◽  
Surface Crystallization ◽  
X Ray Diffraction ◽  
Crystalline Layer ◽  
Surface Conditions ◽  
X Ray ◽  
Treatment Processes ◽  
Electronic Microscope

ZnO-Al2O3-SiO2 glasses with different surface conditions were surface crystallized by different heat treatment process. Differential thermal analysis (DTA), X-ray diffraction analysis (XRD) and scanning electronic microscope (SEM) were used to investigate the crystallization behavior of glasses, the crystalline components and microstructure of the as-got glass-ceramics. According to the DTA results, different heat treatment processes of surface crystallization on the glass were adopted. The SEM results show that surface conditions of glasses are important for the surface crystallization, and the thickness of surface crystalline layer increases with heat treatment time.

Sintering and Crystallization of Glass-Ceramics for Optical Fiber Ferrule

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.

Synthesis and characterization of glass-ceramics prepared from high-carbon ferrochromium slag

RSC Advances ◽  
2016 ◽  
Vol 6 (58) ◽  
pp. 52715-52723 ◽  
Author(s):  
Zhitao Bai ◽  
Guibo Qiu ◽  
Ben Peng ◽  
Min Guo ◽  
Mei Zhang
Keyword(s):  
Heat Treatment ◽  
Bending Strength ◽  
Glass Ceramics ◽  
Synthesis And Characterization ◽  
High Carbon ◽  
Carbon Ferrochrome ◽  
Ferrochrome Slag ◽  
Ferrochromium Slag ◽  
Stage Heat Treatment

The HCFS-based glass-ceramics have been successfully prepared from high carbon ferrochrome slag and waste glass by two-stage heat treatment. The grain size, porosity, microhardness, and bending strength of the glass-ceramics are investigated.

Investigations of lithium-chloro-borate glass-ceramic and its elastic properties

2010 ◽  
Vol 88 (8) ◽  
pp. 569-574 ◽  
Author(s):  
Y. Shivaprakash ◽  
R. V. Anavekar
Keyword(s):  
Heat Treatment ◽  
Elastic Properties ◽  
Glass Ceramic ◽  
Treatment Time ◽  
Poisson Ratio ◽  
Glass Ceramics ◽  
Heat Treatment Time ◽  
Shear Moduli ◽  
Ir Studies ◽  
Precursor Glass

Elastic properties and microstructural studies of 0.3Li2O-0.2LiCl-0.5B2O3 glass-ceramics have been carried out for a precursor glass prepared using the rapid melt quenching technique. Quenched glasses were heat treated (by three step process) at 150 °C for 2, 4, 6, and 8 h. Scanning electron microscopy and X-ray diffraction studies clearly indicate gradual growth of different phases in the glass matrix with increasing time of heat-treatment. IR studies reveal the structural modification in the network as the precursor glass transformed into glass-ceramic. Elastic properties have been measured by performing ultrasonic wave velocity measurements at a frequency of 10 MHz. Longitudinal and shear moduli of the samples tend to increase with heat-treatment time. However, the bulk modulus is almost insensitive to heat treatment. The Debye temperature was found to increase, and the Poisson ratio lies in the range 0.2–0.3 (typical for covalently bonded networks) with an increase in heat-treatment time.

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