Chemical Compositions and Production Technology of Glass-Ceramics

1970 ◽  
pp. 193-274 ◽  
Author(s):  
Anatolii I. Berezhnoi
Keyword(s):  
Production Technology ◽  
Glass Ceramics ◽  
Chemical Compositions

Effect of ZrO2 on Mechanical and Biological Properties of Calcium Phosphate-Based Glass-Ceramics for Biomedical Applications

2008 ◽  
Vol 368-372 ◽  
pp. 1429-1432 ◽  
Author(s):  
Cai Yun Zheng ◽  
Shu Jun Li ◽  
Yu Lin Hao ◽  
Rui Yang
Keyword(s):  
Adverse Effect ◽  
Calcium Phosphate ◽  
Body Fluid ◽  
Biomedical Applications ◽  
Bending Strength ◽  
Glass Ceramics ◽  
Biological Properties ◽  
Chemical Compositions ◽  
Micro Hardness ◽  
Three Point Bending

The effect of ZrO2 addition on mechanical and biological properties of bioactive glass-ceramics with chemical compositions of 60CaO-30P2O5-3TiO2-xZrO2-(7-x)Na2O (x=0,1,3) was investigated. It was found that ZrO2 addition up to 3 mol% contributes to monotonical increase of the glass transition temperature. The micro-hardness increases slightly by 1 mol% ZrO2 addition and keeps constant with further addition whereas 1 mol% ZrO2 addition results in ~20% increase of three-point bending strength. When the specimens were soaked in simulated body fluid, complete apatite layers were formed on the specimens regardless of the ZrO2 addition. It is therefore concluded that the toughening contribution of 1 mol% ZrO2 addition has no adverse effect on the bioactivity of calcium phosphate glass-ceramics.

Feasibility of Producing Glass-Ceramics from a Mixture of Glass Cullet-Eggshell and Perlite

2018 ◽  
Vol 766 ◽  
pp. 139-144
Author(s):  
Patiphan Nakkam ◽  
Napat Chantaramee
Keyword(s):  
Weight Loss ◽  
Chemical Resistance ◽  
Sodium Hydroxide Solution ◽  
Glass Ceramics ◽  
Soda Lime ◽  
Nucleating Agent ◽  
Chemical Compositions ◽  
Glass Cullet ◽  
X Ray Diffraction ◽  
X Ray

Feasibility of producing glass-ceramics from cullet, eggshell and perlite was investigated. In this study, a nucleating agent was synthesized from calcined eggshell and expanded perlite prior to blend with soda-lime waste glass, and then sintered at temperatures ranging from 850 to 1050°C at a heating rate of 10°C/min for 30 - 180 minutes. The crystallization behavior of glass-ceramics was investigated by means of X-ray diffraction analysis and surface morphology, and the chemical compositions were evaluated by scanning electron microscopy and energy dispersive X-ray spectroscopy. Results showed that crystalline phase embedded in the glass phase were needle-like crystal of wollastonite, cristobalite and quartz. According to the chemical resistance test, the obtained glass-ceramics showed acceptable corrosion resistance particularly in acidic environment. The weight loss for glass-ceramics immersed in 1wt% of sodium hydroxide solution was 0.28 - 0.50 wt%, while weight loss due to 1vol% of sulfuric acid solution was 0.04 - 0.16 wt%.

scholarly journals Optical and Mechanical Properties of Highly Translucent Dental Zirconia

Materials ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3395
Author(s):  
Hee-Kyung Kim
Keyword(s):  
Mechanical Properties ◽  
Bending Strength ◽  
Fluorescence Emission ◽  
Glass Ceramics ◽  
Secondary Phase ◽  
Lithium Disilicate ◽  
Sintering Behavior ◽  
Chemical Compositions ◽  
Strong Impact ◽  
Dental Ceramics

The aim was to evaluate the translucency, opalescence, and fluorescence of highly translucent zirconia, lithium disilicate, and bovine teeth. One mm-thick specimens of five monolithic zirconia systems, two glass-ceramics, and bovine enamel/dentin were investigated. A spectrophotometer (Ci7600) was used to measure the CIELab color coordinates, and the translucency and opalescence values were obtained. For evaluating the fluorescence emission, the differences in spectral reflectance by the UV component of illumination were calculated. The microstructures of ceramic specimens were examined with a scanning electron microscope and the chemical compositions were determined with an X-ray fluorescence spectrometer. Mechanical properties were appraised with three-point bending strength, indentation fracture toughness, and Vickers hardness. Data were analyzed using a one-way ANOVA, followed by Tukey’s multiple comparison test (α = 0.05). A higher yttria content (5 mol%) significantly improved the translucency of zirconia ceramics, while they were less translucent than lithium disilicate (p < 0.05). Lowering the alumina content below 0.05 wt.% enhanced the translucency (p < 0.05), but a small amount of alumina was still required to obtain full densification. 0.05 wt.% Fe was used to increase the chroma of zirconia specimens without compromising their mechanical properties. The Er-containing zirconia specimen showed a maximal fluorescence emission at 430 nm. The degree of opalescence was affected by the microstructures of ceramic materials. The microstructure, incorporation of a secondary phase, and sintering behavior can have a strong impact on the final mechanical and optical properties of dental ceramics. Addition of small amounts of metal oxides can affect the translucency, opalescence or fluorescence qualities of zirconia

Bioactive Glass-Ceramic Porous Sinters

2006 ◽  
Vol 49 ◽  
pp. 103-108
Author(s):  
R. Sindut ◽  
Katarzyna Cholewa-Kowalska ◽  
Maria Łączka
Keyword(s):  
Bioactive Glass ◽  
Glass Ceramic ◽  
Sol Gel ◽  
Glass Ceramics ◽  
Diffraction Method ◽  
Thin Layers ◽  
Molar Ratio ◽  
Chemical Compositions ◽  
Bioactive Materials

Bioglasses and bioactive glass-ceramics have found increasingly wide application in medicine and dentistry. Using sol-gel method, is possible to obtain glass and glass-ceramic bioactive materials of new generation, characterized the higher bioactivity than melted bioglasses. These materials can be produced in various final forms, as powders, thin layers on different base and porous sinters. Production of porous bioactive sinters from gel-derived powders is a new problem and the parameters controlling this process are not recognized yet. The aim of the study was to obtain porous bioactive sinters from gel-derived powders of the SiO2-CaO-P2O5 system of four various chemical compositions (S2, II, I, A2) and the characterization of properties of these new materials. The starting powders differ from each other in the content of the basic components, at the molar ratio of CaO to SiO2 equals 0.2-1.35. To obtain the porous sinters a method of burning additions and deposition of the casting slip on the polymeric sponge was used. Sintering was realized in several stages, at the maximal temperature 1200oC. By selecting appropriate conditions of sintering, a durable material of high open porosity up to 77 % was obtained. Its porous structure was characterized by a prevailing number of small micropores of similar dimensions, uniformly distributed in the material. The phase composition of obtained sinters was determined by the X-ray diffraction method. All sinters represented glass-ceramic materials with apatite, cristoballite and calcium silicates as a main crystalline phases. In order to preliminary determination bioactivity of obtained sinters, test in vitro in simulated body fluid SBF was conducted. It was found that hydroxyapatite formation on the sinter surface occurs only in the case of biomaterials of highest calcium concentration.

scholarly journals Evaluating the Effects of Chemical Composition on Induction Heating Ability of Fe2O3-CaO-SiO2Glass Ceramics

2016 ◽  
Vol 2016 ◽  
pp. 1-7
Author(s):  
Y. Y. Wang ◽  
B. Li ◽  
Y. L. Yu ◽  
P. S. Tang
Keyword(s):  
Chemical Composition ◽  
Induction Heating ◽  
Sol Gel ◽  
Glass Ceramics ◽  
Chemical Compositions ◽  
Ceramic Samples ◽  
Magnetite Content ◽  
Time Work ◽  
First Time ◽  
The Relationship

In order to investigate the relationship between induction heating ability of Fe2O3-CaO-SiO2glass ceramics and chemical composition, a series of glass ceramic samples with different chemical compositions were prepared by the sol-gel method. The structural, textural, and magnetic properties of the samples were analyzed and correlated with the Fe2O3content. This is the first time work of its kind that evaluates the relationships between induction heating ability and chemical composition of Fe2O3-CaO-SiO2glass ceramics. The results showed that induction heating ability of Fe2O3-CaO-SiO2glass ceramics increased gradually with increasing magnetite content. Also, the induction heating ability became considerably better when a small amount of phosphorus was introduced. This study thus reveals a methodology to control the induction heating ability of Fe2O3-CaO-SiO2glass ceramics through modifying the chemical composition.

The Microstructure of Steatite (Protoenstatite)

1985 ◽  
Vol 43 ◽  
pp. 236-237
Author(s):  
W. E. Lee ◽  
A. H. Heuer
Keyword(s):  
High Frequency ◽  
Glass Ceramics ◽  
Magnesium Silicate ◽  
Beam Current ◽  
Glassy Matrix ◽  
Angle Of Incidence ◽  
X Ray ◽  
Mechanical And Electrical Properties ◽  
Argon Ions ◽  
High Temperature Polymorph

IntroductionTraditional steatite ceramics, made by firing (vitrifying) hydrous magnesium silicate, have long been used as insulators for high frequency applications due to their excellent mechanical and electrical properties. Early x-ray and optical analysis of steatites showed that they were composed largely of protoenstatite (MgSiO3) in a glassy matrix. Recent studies of enstatite-containing glass ceramics have revived interest in the polymorphism of enstatite. Three polymorphs exist, two with orthorhombic and one with monoclinic symmetry (ortho, proto and clino enstatite, respectively). Steatite ceramics are of particular interest a they contain the normally unstable high-temperature polymorph, protoenstatite.Experimental3mm diameter discs cut from steatite rods (∼10” long and 0.5” dia.) were ground, polished, dimpled, and ion-thinned to electron transparency using 6KV Argon ions at a beam current of 1 x 10-3 A and a 12° angle of incidence. The discs were coated with carbon prior to TEM examination to minimize charging effects.

Analytical Electron Microscopy of Ion-Implanted Metals

1985 ◽  
Vol 43 ◽  
pp. 282-285
Author(s):  
D.I. Potter ◽  
M. Ahmed ◽  
K. Ruffing
Keyword(s):  
Electron Microscopy ◽  
Ion Implantation ◽  
Friction And Wear ◽  
Analytical Electron Microscopy ◽  
Chemical Compositions ◽  
Surface Chemical ◽  
Near Surface ◽  
The Past ◽  
Analytical Electron ◽  
Property Changes

Ion implantation, used extensively for the past decade in fabricating semiconductor devices, now provides a unique means for altering the near-surface chemical compositions and microstructures of metals. These alterations often significantly improve physical properties that depend on the surface of the material; for example, catalysis, corrosion, oxidation, hardness, friction and wear. Frequently the mechanisms causing these beneficial alterations and property changes remain obscure and much of the current research in the area of ion implantation metallurgy is aimed at identifying such mechanisms. Investigators thus confront two immediate questions: To what extent is the chemical composition changed by implantation? What is the resulting microstructure? These two questions can be investigated very fruitfully with analytical electron microscopy (AEM), as described below.

TEM/AEM characterization of fine-grained clay minerals in very-low-grade rocks: Evaluation of contamination by empa involving celadonite family minerals

1996 ◽  
Vol 54 ◽  
pp. 694-695
Author(s):  
Gejing Li ◽  
D. R. Peacor ◽  
D. S. Coombs ◽  
Y. Kawachi
Keyword(s):  
Electron Microscopy ◽  
Volcanic Rocks ◽  
Analytical Electron Microscopy ◽  
Metamorphic Rocks ◽  
New Mineral ◽  
Chemical Compositions ◽  
Low Grade ◽  
Fine Grained ◽  
Depth Analysis ◽  
Mineral Aggregates

Recent advances in transmission electron microscopy (TEM) and analytical electron microscopy (AEM) have led to many new insights into the structural and chemical characteristics of very finegrained, optically homogeneous mineral aggregates in sedimentary and very low-grade metamorphic rocks. Chemical compositions obtained by electron microprobe analysis (EMPA) on such materials have been shown by TEM/AEM to result from beam overlap on contaminant phases on a scale below resolution of EMPA, which in turn can lead to errors in interpretation and determination of formation conditions. Here we present an in-depth analysis of the relation between AEM and EMPA data, which leads also to the definition of new mineral phases, and demonstrate the resolution power of AEM relative to EMPA in investigations of very fine-grained mineral aggregates in sedimentary and very low-grade metamorphic rocks.Celadonite, having end-member composition KMgFe3+Si4O10(OH)2, and with minor substitution of Fe2+ for Mg and Al for Fe3+ on octahedral sites, is a fine-grained mica widespread in volcanic rocks and volcaniclastic sediments which have undergone low-temperature alteration in the oceanic crust and in burial metamorphic sequences.

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