scholarly journals EFFECTS OF Nd2O3 ON THE CRYSTALLIZATION AND PROPERTIES OF GLASS CERAMIC IN Li2O–K2O–Al2O3–SiO2–P2O5 SYSTEM

2018 ◽  
Vol 55 (1B) ◽  
pp. 238
Author(s):  
Minh N. H.
Keyword(s):  
Bending Strength ◽  
Glass Ceramics ◽  
X Ray Diffraction ◽  
Lithium Metasilicate ◽  
Degree Of Crystallization ◽  
C 30 ◽  
High Degree ◽  
Dental Restorative ◽  
Stage Heat Treatment ◽  
P2o5 System

Glass ceramics (GCs), which often contain a small amount of rare earth oxides to improve their performance, are ideal for dental restorative applications. The aim of this study was to investigate the various effects of Nd2O3 content (0–1 wt%) on crystallization and properties of GC derived from Li2O–K2O–Al2O3–SiO2–P2O5 system. The glass blocks were formed from the molten at 1450 °C. Based on the DTA results, the glass samples were experienced by two–stage heat–treatment (600 °C/ 90 min + 720 °C/ 30 min) to change to ingots. After that, the ingot samples were fired in a hot pressing furnace EP3000 at 930 °C for 30 min. The results of powder X–ray diffraction (XRD) indicated that the final GCs contained crystals such as lithium disilicate (Li2Si2O5 or LS2), lithium metasilicate (Li2SiO3 or LS) and the traces of lithium phosphate (Li3PO4). With increasing Nd2O3 content, the relative amount of LS phase increased slightly while LS2 phase decreased. However, the final GC containing 0.75 wt% Nd2O3 had the highest bending strength at 293 MPa, the lowest chemical solubility and relative high Vicker hardness. These samples had a high degree of crystallization and the highest relative content of desired LS2 phase.

scholarly journals The effect of replacing iron atoms instead of zinc of the quaternary compound CZTS

2021 ◽  
Vol 2114 (1) ◽  
pp. 012033
Author(s):  
Abubaker.S. Mohammed
Keyword(s):  
Full Width Half Maximum ◽  
Energy Gap ◽  
Film Surface ◽  
X Ray Diffraction ◽  
Quaternary Compound ◽  
Force Microscopy ◽  
Atomic Force ◽  
Coating Method ◽  
Degree Of Crystallization ◽  
High Degree

Abstract In this article, the quaternary compound Cu2MSnS4 was prepared in a simple and inexpensive approach, where M is the iron (Fe) and zinc (Zn) atoms by the spin coating method on a glass substrate at room temperature (RT), as a result of replacing Zn atoms by Fe. Quaternary Cu2ZnSnS4 (CZTS) and Cu2FeSrS4 (CFTS) structural and optical properties have been studied successfully. The material has been identified by X-ray diffraction, and it was discovered that CZTS has a polycrystalline Tetragonal (kesterite) structure, whereas CFTS has a Tetragonal (stannite) structure. A reduction in the full width half maximum (FWHM) of the preferred plane implies a high degree of crystallization. The structural properties of the film surface, such as grain size and roughness, were studied by Atomic force microscopy (AFM). The results explain an increase in nanoparticle size and surface roughness when Fe is substituted by Zn in the CZTS structure. The absorption coefficient values of all designed compounds in visible regions are greater than 104/cm, and the results show that the absorbance coefficient increases with Fe add. The CZTS films showed an energy gap of 1.88 eV, and this value became 1.69 eV with substituted Fe instead of Zn.

Structure Characterization of Sintered CaO-Al2O3-SiO2 Glass-Ceramic Reinforced with Spodumene

2013 ◽  
Vol 834-836 ◽  
pp. 309-314
Author(s):  
Zi Fan Xiao ◽  
Jin Shu Cheng ◽  
Jun Xie
Keyword(s):  
Glass Ceramic ◽  
Energy Dispersive Spectrometry ◽  
Crystal Size ◽  
Bending Strength ◽  
Glass Ceramics ◽  
Structure Characterization ◽  
X Ray Diffraction ◽  
Crystalline Phases ◽  
X Ray

A glass-ceramic belonging to the CaO-Al2O3-SiO2(CAS) system with different composition of spodumene and doping the Li2O with amount between 0~2.5 % (mass fraction) were prepared by onestage heat treatment, under sintering and crystallization temperature at 1120 °C for two hours. In this paper, differential thermal analysis, X-ray diffraction, scanning electron microscopy, energy dispersive spectrometry and bending strength test were employed to investigate the microstructure and properties of all samples. β-wollastonite crystals were identified as the major crystalline phases, and increasing Li2O was found to be benefit for the crystallization and tiny crystalline phases remelting, resulting in the content of major crystalline phases increased first and then decreased with increasing the expense of spodumene. Meanwhile, the crystal size can be positively related with the content of Li2O. The preferable admixed dosage of spodumene can be obtained, besides the strength of glass-ceramics can be more than 90 MPa.

Effect of ZrO2 and MgO doping on microstructure and properties of translucent alumina fabricated by rapid vacuum sintering

2018 ◽  
Vol 11 (05) ◽  
pp. 1850040
Author(s):  
Yaming Zhang ◽  
Haixia Guo ◽  
Bo Wang ◽  
Jianfeng Yang
Keyword(s):  
Grain Size ◽  
Bending Strength ◽  
Synergetic Effect ◽  
High Heating Rate ◽  
Vacuum Sintering ◽  
Co Doping ◽  
Total Transmission ◽  
Mean Grain Size ◽  
C 30 ◽  
Dental Restorative

Translucent alumina doped with ZrO2 and MgO was fabricated by two-step vacuum sintering (1475[Formula: see text]C/30[Formula: see text]min followed by 1320[Formula: see text]C/20[Formula: see text]min) with a high heating rate (80[Formula: see text]C/min). Densification, grain size, phase composition, mechanical properties and translucency of the alumina were investigated. The results indicated that co-doping of ZrO2 and MgO showed a synergetic effect on grain refinement and densification process. On one hand, the solubility of MgO in alumina was increased by the ZrO2 additive, which was favorable for the densification. On the other hand, more favorable ZrO2 accommodation sites existed at the alumina grain boundaries created by the MgO, effectively decreasing the grain size. Finally, the sample with porosity of 0.5% and mean grain size of 1.21[Formula: see text][Formula: see text]m was obtained at a co-doped content of 0.35[Formula: see text]wt.% of ZrO2 and MgO (mass ratio of 1:1). The co-dopants led to the enhanced hardness and bending strength as well as a favorable fracture toughness of the translucent alumina, when compared with the MgO single-doped and doping free samples. Moreover, total transmission of as high as 51% and good translucency was also obtained. The improved properties widened the prospect of the translucent alumina used as dental restorative materials.

Effect of CaO/SiO2 Ratio and TiO2 on Glass-Ceramics Made from Steel Slag and Fly Ash

2012 ◽  
Vol 217-219 ◽  
pp. 119-123 ◽  
Author(s):  
Bao Wei Li ◽  
Hua Chen ◽  
Ming Zhao ◽  
Xue Feng Zhang ◽  
Yong Sheng Du ◽  
...  
Keyword(s):  
Fly Ash ◽  
Bending Strength ◽  
Steel Slag ◽  
Glass Ceramics ◽  
Nucleating Agent ◽  
Spherical Particles ◽  
X Ray Diffraction ◽  
X Ray ◽  
Main Crystalline Phase ◽  
Average Size

Glass ceramics of the CaO-MgO-Al2O3-SiO2 system were fabricated by adopting the melting-casting procedure. Steel slag and fly ash were used as the major starting materials. The influence of CaO/SiO2 Ratio variations on the microstructure and mechanical properties were investigated using X-ray diffraction, scanning electron microscopy and property measurements. Augite is identified as the main crystalline phase of the as studied glass ceramics. The average size of augite grains in form of spherical particles is found within the range of 100-250nm. The bending strength of the glass-ceramics could reach as high as 170.74MPa. Increasing CaO/SiO2 show a beneficial influence on the crystallization of glass ceramics, and its effectiveness is inferior compared with that of increasing addition of nucleating agent, TiO2.

Effect of MgO/Al2O3 Ratio on Properties and Crystallization of Glass-Ceramics

2014 ◽  
Vol 1065-1069 ◽  
pp. 1879-1883
Author(s):  
Jun Jie Hou ◽  
Yan Bing Zong ◽  
Zhao Bo Liu ◽  
Da Qiang Cang
Keyword(s):  
Bending Strength ◽  
Raw Materials ◽  
Glass Ceramics ◽  
X Ray Diffraction ◽  
X Ray ◽  
Slag Glass ◽  
Higher Temperature ◽  
Dta Curves ◽  
Furnace Slag ◽  
Crystallization Of Glass

Reduction electric furnace slag, quartz sand and soapstone were used as the raw materials for preparation of glass-ceramics according to their compositions and characteristics. Differential thermal analysis, X-ray diffraction, scanning electron microscopy were used to investigate the crystallization mechanism, microstructure and main mechanical properties of slag glass-ceramics with different mass ratios of MgO/Al2O3. The exothermic peaks of the DTA curves shift to higher temperature with the decrease of MgO/Al2O3ratio. And along with the decreasing of the MgO/Al2O3, the crystallization of the glass-ceramics also decreased. The bending strength can reach 153.09MPa when the MgO/Al2O3ratio is 3.03.

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.

Sintering Behavior of LZS Glass-Ceramics

2012 ◽  
Vol 727-728 ◽  
pp. 1028-1033 ◽  
Author(s):  
Jaime Domingos Teixeira ◽  
Antonio Pedro Novaes de Oliveira ◽  
Lourival Boehs ◽  
Francielly Roussenq Cesconeto ◽  
Cristina Siligardi ◽  
...  
Keyword(s):  
Glass Powder ◽  
Bending Strength ◽  
Glass Ceramics ◽  
Thermal Shrinkage ◽  
Sintering Behavior ◽  
Maximum Hardness ◽  
X Ray Diffraction ◽  
Time Intervals ◽  
X Ray ◽  
Powder Compacts

Sintering and crystallization behaviors of a LZS glass-powder were investigated by means of thermal shrinkage, differential thermal analysis, X-ray diffraction as well as density and mechanical properties measurements. The melted glass, 9.56Li2O.22.36ZrO2.68.08SiO2(wt%) first was cast into water to provide a frit for milling. The milled glass powder (mean particle size 5.0 µm) was then uniaxially pressed at 100 MPa and the obtained samples were isothermally sintered in the 800-950°C temperature range in air for appropriated time intervals (15-120 min). Sintering was found to start at about 640°C and crystallization took place just after completion of sintering and was almost complete at 920°C. The glass powder compacts crystallized into lithium and zircon silicates so that glass-ceramics with relative densities between 84 and 99% were obtained reaching maximum hardness and bending strength values of 8 ± 0.5 GPa and 214 ± 20 MPa, respectively.

Transparent Glass-Ceramics Derived from Spontaneously Crystallized Phosphosilicte Glasses

2011 ◽  
Vol 239-242 ◽  
pp. 1096-1100
Author(s):  
Shu Jiang Liu ◽  
Yan Fei Zhang
Keyword(s):  
Glass Ceramics ◽  
Compositional Variation ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Rich Phase ◽  
Transparent Glass ◽  
X Ray ◽  
Phosphosilicate Glass ◽  
Degree Of Crystallization ◽  
Good Transparency

Transparent phosphosilicate glass-ceramics were prepared by heating the spontaneously crystallized precursor glasses in which crystals have formed during cooling of the melts. And the effects of compositional variation on the crystalline phases, degree of crystallization and transparency were investigated by using X-ray diffraction (XRD), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). It is found that Mg2+tends to exist in silicate-rich phase rather than phosphate-rich phase, such MgO is more beneficial to the transparency of phosphosilicate glass-ceremics compared to CaO. In addition, the substitution of P2O5for SiO2enhances the tendency of phase separation, and hence the precipitation of Na2MgSiO4crystals for the precursor glasses as well as glass-ceramics with good transparency.

Synthesis and characterization of multiphase bioactive glass-ceramics in the CaO–MgO–SiO2 system with B2O3 additive

2008 ◽  
Vol 23 (11) ◽  
pp. 2873-2879 ◽  
Author(s):  
Xianchun Chen ◽  
Yan Wei ◽  
Zhongbing Huang ◽  
Yunqing Kang ◽  
Guangfu Yin
Keyword(s):  
Bending Strength ◽  
Coefficient Of Thermal Expansion ◽  
Glass Ceramics ◽  
Nominal Composition ◽  
Apatite Formation ◽  
X Ray Diffraction ◽  
Cell Growth And Viability ◽  
Bonelike Apatite

A glass-ceramic (GC0) with nominal composition of 51.2% CaO–12.1% MgO–36.7% SiO2 (wt%) was synthesized. Then multiphase glass-ceramics of MGC1 and MGC2 were obtained by adding 1 and 2 wt% B2O3 to GC0 followed by thermal treatment. The bending strength of MGC1 was the highest, about 89.46 MPa, and the coefficient of thermal expansion was 10.67 × 10−6 °C−1, closer to that of Ti–6Al–4V alloy (10.03 × 10−6 °C−1). X-ray diffraction analysis confirmed that MGC1 was predominantly composed of akermanite, merwinite, and small amounts of dicalcium silicate crystalline phases. The bioactivity and cytocompatibility in vitro of MGC1 were detected by investigating the bonelike apatite-formation ability in simulated body fluid (SBF) and osteoblast morphology and viability. The results showed that MGC1 possessed bonelike apatite-formation ability in SBF and could release ionic products to significantly stimulate cell growth and viability. Furthermore, osteoblasts adhered and spread well on MGC1, indicating good bioactivity and potential cytocompatibility.

Physical-Mechanical Behaviour of a LZS Glass-Ceramic

2014 ◽  
Vol 775-776 ◽  
pp. 599-603 ◽  
Author(s):  
Jaime Domingos Teixeira ◽  
Manuel Alfredo Pereira ◽  
Lourival Boehs ◽  
Cristina Siligardi ◽  
Vicente Cantavella ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Analysis ◽  
Glass Ceramic ◽  
Modulus Of Elasticity ◽  
Bending Strength ◽  
Glass Ceramics ◽  
Physical And Mechanical Properties ◽  
Maximum Hardness ◽  
X Ray Diffraction ◽  
X Ray

Physical and mechanical properties of a glass-ceramic belonging to the LZS (Li2O-SiO2-ZrO2) system were investigated by dilatometric analysis, differential thermal analysis, X-ray diffraction and measurements of density, hardness, bending strength, modulus of elasticity and fracture toughness. The obtained glass-ceramics showed ZrSiO4 and Li2Si2O5 as main crystalline phases, relative densities between 84 and 99%, maximum hardness, bending strength, modulus of elasticity and toughness of 8±0.5 GPa, 214±20 MPa, 115±0.42 GPa and 3.65±0.21 MPa.m1/2, respectively.

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