scholarly journals Investigation of the thermal properties of mullite-cordierite materials

2018 ◽  
Vol 118 ◽  
pp. 111-118
Author(s):  
О. V. Savvova ◽  
O. I. Fesenko ◽  
V. D. Timofeеv ◽  
Ya. V. Poviderna
Keyword(s):  
Heat Treatment ◽  
Thermal Properties ◽  
Fire Resistance ◽  
Glass Ceramic ◽  
Linear Expansion ◽  
High Strength ◽  
Ceramic Materials ◽  
Glass Ceramic Materials ◽  
Cordierite Glass ◽  
Coefficient Of Linear Expansion

Based on the analysis of existing mullite-cordierite sitalls, the need to create high-strength materials of this type for individual and local protection against high-speed loads has been determined. They should be characterized by lower cost, due to low-temperature short-term heat treatment using domestic raw materials. An important aspect of ensuring the effective protective effect of an armor-element, in addition to its armor resistance and survivability, is the ability to withstand the effects of open flame and combustible mixtures, which is determined by the thermal properties of the sitalls. The aim of this work is to study the thermal properties, namely thermal expansion coefficient and fire resistance, high strength mullite-cordierite glass-ceramics that they are developed by us earlier. The temperature coefficient of linear expansion was determined using a quartz vertical dilatometer QVD-5A (ASTM C 372-94 (2007)), fire resistance according to GOST 33000—2014. According to X-ray diffraction and differential thermal analyzes, the experimental samples were divided into two groups according to the formation mechanism of structure and phase composition of glass materials during heat treatment. For each of the materials groups, the influence of the chemical and phase compositions on the thermal coefficient of linear expansion of the original mullite-cordierite glass materials and glass-ceramic materials (sitalls) thermally treated using two-stage heat treatment was determined. The study of the fire resistance of the developed glass-ceramic materials made it possible to establish that they withstand the thermal load in a certain mode for 360 minutes. It has been established that providing high thermal- and fire resistance (RE 360 (h)) is a determining factor in the production of hardened glass crystalline materials that are able to resist to thermal destroying at sharp temperature change.

scholarly journals Solid Solutions Formation Mechanism in Cordierite-Mullite Glass Materials During Ceramization

2020 ◽  
Vol 14 (4) ◽  
pp. 583-589
Author(s):  
Оksana Savvova ◽  
◽  
Hennadiy Voronov ◽  
Оlena Babich ◽  
Oleksii Fesenko ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Formation Mechanism ◽  
Glass Ceramic ◽  
High Strength ◽  
Ceramic Materials ◽  
Ceramic Coatings ◽  
Resource Saving ◽  
Aluminosilicate Glasses ◽  
Glass Ceramic Materials ◽  
Fine Crystalline Structure

Relevance of the development of high-strength glass-ceramic coatings obtained by resource-saving technology for protective elements has been established. Structure formation mechanism in magnesium aluminosilicate glasses during heat treatment has been analyzed. Selection of the system was substantiated, model glasses and glass-ceramic materials on its base have been developed. Patterns of structure regularity and formation of the phase composition of glass-ceramic materials during their ceramization have been investigated. It was established that the presence of crystalline phase of mullite after melting leads to formation of the primary crystals and allows the formation of the fine crystalline structure under conditions of the low-temperature heat treatment at the nucleation stage. Developed high-strength glass ceramic materials can be used as a base in creating protective elements for special-purpose vehicles by energy-saving technology.

scholarly journals Preparation of basalt-based glass ceramics

2003 ◽  
Vol 68 (6) ◽  
pp. 505-510 ◽  
Author(s):  
Branko Matovic ◽  
Snezana Boskovic ◽  
Mihovil Logar
Keyword(s):  
Optical Microscopy ◽  
Phase Analysis ◽  
Glass Ceramic ◽  
Glassy Phase ◽  
Raw Materials ◽  
Glass Ceramics ◽  
High Strength ◽  
Ceramic Materials ◽  
X Ray ◽  
Glass Ceramic Materials

Local and conventional raw materials?massive basalt from the Vrelo locality on Kopaonik mountain?have been used as starting materials to test their suitability for the production of glass-ceramics. Crystallization phenomena of glasses of the fused basalt rocks were studied by X-ray phase analysis optical microscopy and other techniques. Various heat treatments were used and their influences, on controlling the microstructures and properties of the products were studied with the aim of developing high strength glass-ceramic materials. Diopside CaMg(SiO3)2 and hypersthene ((Mg,Fe)SiO3) were identifies as the crystalline phases. The final products contained considerable amounts of a glassy phase. The crystalline size was in range of 8?480 ?m with plate or needle shape. Microhardness, crashing strength and wears resistence of the glass-ceramics ranged from 6.5?7.5, from 2000?6300 kg/cm2 and from 0.1?0.2 g/cm, respectively.

scholarly journals Energy Transfer Study on Tb3+/Eu3+ Co-Activated Sol-Gel Glass-Ceramic Materials Containing MF3 (M = Y, La) Nanocrystals for NUV Optoelectronic Devices

Materials ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2522 ◽  
Author(s):  
Natalia Pawlik ◽  
Barbara Szpikowska-Sroka ◽  
Wojciech A. Pisarski
Keyword(s):  
Heat Treatment ◽  
Energy Transfer ◽  
Glass Ceramic ◽  
Sol Gel ◽  
Optoelectronic Devices ◽  
Emission Spectra ◽  
Ceramic Materials ◽  
Near Ultraviolet ◽  
Glass Ceramic Materials ◽  
Significant Prolongation

In the present work, the Tb3+/Eu3+ co-activated sol-gel glass-ceramic materials (GCs) containing MF3 (M = Y, La) nanocrystals were fabricated during controlled heat-treatment of silicate xerogels at 350 °C. The studies of Tb3+ → Eu3+ energy transfer process (ET) were performed by excitation and emission spectra along with luminescence decay analysis. The co-activated xerogels and GCs exhibit multicolor emission originated from 4fn–4fn optical transitions of Tb3+ (5D4 → 7FJ, J = 6–3) as well as Eu3+ ions (5D0 → 7FJ, J = 0–4). Based on recorded decay curves, it was found that there is a significant prolongation in luminescence lifetimes of the 5D4 (Tb3+) and the 5D0 (Eu3+) levels after the controlled heat-treatment of xerogels. Moreover, for both types of prepared GCs, an increase in ET efficiency was also observed (from ηET ≈ 16% for xerogels up to ηET = 37.3% for SiO2-YF3 GCs and ηET = 60.8% for SiO2-LaF3 GCs). The changes in photoluminescence behavior of rare-earth (RE3+) dopants clearly evidenced their partial segregation inside low-phonon energy fluoride environment. The obtained results suggest that prepared SiO2-MF3:Tb3+, Eu3+ GC materials could be considered for use as optical elements in RGB-lighting optoelectronic devices operating under near-ultraviolet (NUV) excitation.

High-strength glass-ceramic materials synthesized in a large solar furnace

2015 ◽  
Vol 51 (3) ◽  
pp. 202-205 ◽  
Author(s):  
I. G. Atabaev ◽  
Sh. A. Faiziev ◽  
M. Paizullakhanov ◽  
Zh. Z. Shermatov ◽  
O. Razhamatov
Keyword(s):  
Glass Ceramic ◽  
High Strength ◽  
Ceramic Materials ◽  
Solar Furnace ◽  
Glass Ceramic Materials

Development of High-Strength Glass–Ceramic Materials by Utilization of Slag Discharged from Steel-Making Industry in Korea

2016 ◽  
Vol 8 (12) ◽  
pp. 2295-2298
Author(s):  
Dongyoon Shin ◽  
Duk-Hee Lee ◽  
Mijung Yoon ◽  
Hyun Seo Park ◽  
Sung Mo Seo ◽  
...  
Keyword(s):  
Glass Ceramic ◽  
High Strength ◽  
Ceramic Materials ◽  
Steel Making ◽  
Glass Ceramic Materials

Transformation toughening of glass ceramics

1987 ◽  
Vol 2 (6) ◽  
pp. 801-804 ◽  
Author(s):  
D. R. Clarke ◽  
B. Schwartz
Keyword(s):  
Glass Ceramic ◽  
Tetragonal Zirconia ◽  
Glass Ceramics ◽  
Ceramic Materials ◽  
Nucleation Event ◽  
Transformation Toughening ◽  
Glass Ceramic Materials ◽  
Polycrystalline Ceramic ◽  
Cordierite Glass ◽  
Processing Techniques

The utilization of transformation toughening has hitherto been restricted to increasing the fracture resistance of polycrystalline ceramic materials. Although a number of investigators have attempted to extend the concept to toughening glasses and glass ceramics with tetragonal zirconia, no successful reports have been published. It is argued that the approaches employed are inevitably limited primarily because they do not take into account the necessity of nucleating the tetragonal-to-monoclinic transformation away from the crack tip itself. By concentrating on the nucleation event and using standard ceramic processing techniques, it has been demonstated that transformation toughening can be used to increase the toughness of glass-ceramic materials, and this approach is illustrated by increasing the fracture toughness of a cordierite glass ceramic.

High-Strength Spodumene Glass-Ceramic Materials

2017 ◽  
Vol 49 (3) ◽  
pp. 479-486 ◽  
Author(s):  
O. V. Savvova ◽  
O. V. Babich ◽  
G. K. Voronov ◽  
S. O. Ryabinin
Keyword(s):  
Glass Ceramic ◽  
High Strength ◽  
Ceramic Materials ◽  
Glass Ceramic Materials

scholarly journals Alumina silicate glass-ceramic materials for electrical purposes

2020 ◽  
Vol 120 ◽  
pp. 174-185
Author(s):  
O. V. Savvova ◽  
G. K. Voronov ◽  
S. A. Ryabinin ◽  
E. Yu. Fedorenko ◽  
V. D. Timofeev
Keyword(s):  
Heat Treatment ◽  
Phase Composition ◽  
Electrical Properties ◽  
Silicate Glass ◽  
Glass Ceramic ◽  
Breakdown Strength ◽  
Chemical Properties ◽  
Ceramic Materials ◽  
Silicate System ◽  
Glass Ceramic Materials

The prospects for use of glass-ceramic materials as electrical products were analyzed. The priority of a self-organized macro- and nanostructure formation of the glass-ceramic materials under conditions of low-temperature heat treatment to ensure their high physical and chemical properties was shown. The choice of an alumina silicate system of materials for obtaining high-strength glass-ceramic materials with improved electrical properties was substantiated, taking into account the aspects of energy saving. The technological modes of cooking, forming and heat treatment of glass-ceramic materials were determined. Resistance, dielectric constant and dielectric loss tangent at 106 Hz were measured using an E6-13A teraometer on a trielectrode system at a temperature of +29 °C and a DE-5000 RLC meter. Electric strength (Em) and cold crushing strength were determined according to GOST 24409-80. Tensile strength according to GOST 32281.1-2013 (EN 1288-1: 2000). The decisive influence on the electrical properties of glass-ceramic materials the crystalline phases of α-cordierite, β-spodumene or lithium disilicate, as well as the residual glass phase composition has been established. The structure influence of the alumina silicate glass-ceramic materials on the provision of their electrical (tgδ∙104 = 70 ÷ 80; ε = 8.0 ÷ 9.3 (at f = 106 Hz); lg ρv = 12.9 ÷ 15.0 (ρv, Ohm·cm at Т = 20 °C) and mechanical (K1C = 3.15 ÷ 4.3 МPа∙м1/2; σ comp = 630 ÷ 700 МPа, σbend = 300 ÷ 350 МPа; KCU = 4.8 ÷ 5.9 kJ/m2) properties. It was found that, the defining condition for the developed glass-ceramic materials use as insulating materials under repeated exposure to high-temperature operations is their high breakdown strength Em = 37 ÷ 42 MV/m and thermal shock resistance due to low TCLE (α∙107 = 21.5 ÷ 31.8 deg-1). The influence of phase composition and structure of the alumina silicate glass-ceramic materials on their electrical and mechanical properties was analyzed. A comparative assessment of the known ceramic and glass-ceramic materials for electrical purposes has made it possible to establish the feasibility of using the developed materials as substrates in the design of a hybrid integrated circuit, vacuum-tight shell and capacitor dielectrics.

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