Wear and Erosion Resistant Ceramic Materials

2021 ◽  
Author(s):  
Pavol Hvizdoš
Keyword(s):  
Ceramic Materials ◽  
Resistant Ceramic

scholarly journals The refractory compositions designing for the highly-heat-resistant ceramic products in the foundry practice

2018 ◽  
pp. 18-23
Author(s):  
M. S. Varfolomeev ◽  
G. I. Shcherbakova
Keyword(s):  
Ceramic Materials ◽  
Thermal And Mechanical Properties ◽  
Heat Resistant ◽  
Magnesium Compounds ◽  
Different Temperatures ◽  
Bonding Phase ◽  
Heat Resistant Metals ◽  
Α Al2o3 ◽  
Semidry Pressing ◽  
Resistant Ceramic

The sintering peculiarities of the ceramic materials which had been prepared by means of semidry pressing are investigated in the article. The fillers were the yttrium oxide Y2O3 and the fused corundum α-Al2O3, the bonding phase was the aluminoxane addition either pure or modified by the yttrium and magnesium compounds. We investigated the processes occurring at the examined ceramics sintering at different temperatures and their influence on the obtained ceramics properties. The phase composition, the thermal and mechanical properties of the test samples at 1500 °C are presented. The produced test ceramic crucibles have advanced thermal resistance and stability against the thermal cycling. The possibility is regarded to use the developed ceramic crucibles for melting and casting of the chemically reactive highly-heat-resistant metals and alloys.

Acid resistant ceramic materials produced using industrial waste products

1988 ◽  
Vol 45 (1) ◽  
pp. 34-38
Author(s):  
G. G. Gaprindashvili ◽  
M. K. Kekelidze ◽  
L. K. Tedeishvili
Keyword(s):  
Industrial Waste ◽  
Ceramic Materials ◽  
Waste Products ◽  
Resistant Ceramic

scholarly journals Regularities of phase formation, structure and properties of chemically and thermally resistant ceramic materials

2018 ◽  
Vol 118 ◽  
pp. 119-131
Author(s):  
M. I. Ryschenko ◽  
O. Yu. Fedorenko ◽  
M. Yu. Lisytkina ◽  
O. V. Shevtsov ◽  
K. V. Bіlohubkina ◽  
...  
Keyword(s):  
Phase Composition ◽  
Phase Formation ◽  
Firing Temperature ◽  
Porous Ceramic ◽  
Ceramic Materials ◽  
Porous Ceramics ◽  
Structure And Properties ◽  
Sintered Ceramic ◽  
Water Permeability Coefficient ◽  
Resistant Ceramic

Based on the compositions of MgO—Al2O3—TiO2—SiO2 system, the chemically and thermally resistant ceramic was obtained at a firing temperature of 1250 °C by the directed synthesis of tialite and mullite phases. The influence of alternative raw materials of natural and technogenic origin on the operational properties and phase composition of porous and densely-sintered ceramic materials was studied. The using expediency of pyrophyllite containing waste of quartzite mining and ferrotitanium production wastes as the phase forming components of ceramic masses is established. The mechanism of structure- and phase formation of tialite and mullite-tialite ceramics was investigated. It was established that, stabilization of the tialite phase at a temperature of 1200—1250 oC occurs while maintaining the ratio of TiO2/Al2O3 oxides ~ 1.4 and the presence of 1.3 wt. % Fe2O3, as the mineralizing component included in the waste. The possibility of obtaining tialite containing ceramic materials at a lower firing temperature (1200 oC) due to the formation of a tialite solid solution (Mg0.3Al1.4Ti1.5O5) while maintaining the ratio of MgO : TiO2 oxides = 0.18 was proved. Technological principles of the production of chemically and thermally resistant ceramics both with the densely-sintered and with the porous structure, the total porosity of which is respectively 0.41 and 60 %, have been developed. The permeability of porous ceramic materials of mullitе-tialite composition was determined (water permeability coefficient P = 5.39∙10-5 cm2/s), as well as parameters of sorption processes (diffusion rate of Cr2O7-2 and MnO4- ions is 6.38∙10-6 and 1.06∙10-5 cm2/s respectively). This indicates the possibility of using the developed porous ceramics for the manufacture of industrial wastewater filters. Complex studies of the phase composition, structure and properties of the developed ceramic materials confirmed the promise of their use for the manufacture of parts of equipment operating in corrosive environments.

scholarly journals A Calorimetric Method for Determination of Heat Capacity of Ceramics for Concentrated Solar Thermal Systems / Skenējošās Kalorimetrijas Metode Siltumietilpības Noteikšanai Saules Kolektoru Keramikā

2013 ◽  
Vol 50 (5) ◽  
pp. 68-73 ◽  
Author(s):  
J. Kalnačs ◽  
V. Grehovs ◽  
G. Mežinskis ◽  
L. Bidermanis
Keyword(s):  
Heat Capacity ◽  
Protective Coatings ◽  
Thermal Contact ◽  
Ceramic Materials ◽  
Concentrated Solar Power ◽  
Scanning Calorimetry ◽  
Thermal Systems ◽  
Continuous Scanning ◽  
Resistant Ceramic

Abstract Differential scanning calorimetry was carried out to determine the heat capacity (Cp) of the high temperature resistant ceramic materials to be used as protective coatings for stainless steel tubes of parabolic trough solar collectors in concentrated solar power (CSP) systems. The Ср(Т) measurements and calculations were performed at continuous scanning in the temperature range 20-800 °С. In the work, calibration curves have been derived for conversion of measuring units from mcV into mW. To achieve a better repeatability of measurements, methods for stabilization of the thermal contact between the sample-containing vessel and the probe have been developed. The Ср(Т) dependence was obtained for different ceramic materials.

Examination of Fracture Interfaces in Silicon Nitride

1975 ◽  
Vol 33 ◽  
pp. 60-61
Author(s):  
Nancy J. Tighe
Keyword(s):  
Silicon Nitride ◽  
Grain Boundary ◽  
Crack Growth ◽  
Subcritical Crack Growth ◽  
Slow Crack Growth ◽  
Ceramic Materials ◽  
Grain Boundary Sliding ◽  
Boundary Phase ◽  
Turbine Engines ◽  
Boundary Sliding

Silicon nitride is one of the ceramic materials being considered for the components in gas turbine engines which will be exposed to temperatures of 1000 to 1400°C. Test specimens from hot-pressed billets exhibit flexural strengths of approximately 50 MN/m2 at 1000°C. However, the strength degrades rapidly to less than 20 MN/m2 at 1400°C. The strength degradition is attributed to subcritical crack growth phenomena evidenced by a stress rate dependence of the flexural strength and the stress intensity factor. This phenomena is termed slow crack growth and is associated with the onset of plastic deformation at the crack tip. Lange attributed the subcritical crack growth tb a glassy silicate grain boundary phase which decreased in viscosity with increased temperature and permitted a form of grain boundary sliding to occur.

Stress-Induced Ordering in Y203-Stabilized Tetragonal Zr02

1985 ◽  
Vol 43 ◽  
pp. 222-223
Author(s):  
J. Y. Koo ◽  
M. P. Anderson
Keyword(s):  
Electron Diffraction ◽  
Ionic Conduction ◽  
Electron Diffraction Study ◽  
Ceramic Materials ◽  
Bright Field Image ◽  
Transformation Toughening ◽  
Ion Milling ◽  
Thin Foils ◽  
Carbon Coated ◽  
Convergent Beam

Tetragonal Zr02 has been used as a toughening phase in a large number of ceramic materials. In this system, complex diffraction phenomena have been observed and an understanding of the origin of the diffraction effects provides important information on the nature of transformation toughening, ionic conduction, and phase destabilization. This paper describes the results of an electron diffraction study of Y203-stabilized, tetragonal Zr02 polycrystals (Y-TZP).Thin foils from the bulk Y-TZP sample were prepared by careful grinding and cryo ion-milling. They were carbon coated and examined in a Philips 400T/FEG microscope. Fig. 1 shows a typical bright field image of the 100% tetragonal(t) Zr02. The tetragonal structure was identified by both bulk x-ray diffraction and convergent beam electron diffraction (Fig. 2. A local region within a t-Zr02 grain was subjected to an intense electron beam irradiation which caused partial martensitic transformation of the t-Zr02 to monoclinic(m) symmetry, Fig. 3 A.

Analytical and High-Resolution EM Study of Crystalline Phases formed at Metal-Ceramic Interface

1990 ◽  
Vol 48 (2) ◽  
pp. 426-427
Author(s):  
N. Merk ◽  
A. P. Tomsia ◽  
G. Thomas
Keyword(s):  
Cross Section ◽  
Dissimilar Materials ◽  
Ceramic Materials ◽  
Electron Micrograph ◽  
Scanning Electron Micrograph ◽  
Structural Applications ◽  
Metal Ceramic ◽  
The Subject ◽  
Ceramic Compounds ◽  
Scanning Electron

A recent development of new ceramic materials for structural applications involves the joining of ceramic compounds to metals. Due to the wetting problem, an interlayer material (brazing alloy) is generally used to achieve the bonding. The nature of the interfaces between such dissimilar materials is the subject of intensive studies and is of utmost importance to obtain a controlled microstructure at the discontinuities to satisfy the demanding properties for engineering applications . The brazing alloy is generally ductile and hence, does not readily fracture. It must also wett the ceramic with similar thermal expansion coefficient to avoid large stresses at joints. In the present work we study mullite-molybdenum composites using a brazing alloy for the weldment.A scanning electron micrograph from the cross section of the joining sequence studied here is presented in Fig. 1.

Analytical Electron Microscopy of Surface-Modified Ceramics

1985 ◽  
Vol 43 ◽  
pp. 276-279
Author(s):  
P. S. Sklad
Keyword(s):  
Electron Microscopy ◽  
Analytical Electron Microscopy ◽  
Theoretical Models ◽  
Ceramic Materials ◽  
Solute Concentration ◽  
Second Phase ◽  
Analytical Electron ◽  
Implantation Techniques ◽  
Lattice Damage ◽  
Surface Modified

Over the past several years, it has become increasingly evident that materials for proposed advanced energy systems will be required to operate at high temperatures and in aggressive environments. These constraints make structural ceramics attractive materials for these systems. However it is well known that the condition of the specimen surface of ceramic materials is often critical in controlling properties such as fracture toughness, oxidation resistance, and wear resistance. Ion implantation techniques offer the potential of overcoming some of the surface related limitations.While the effects of implantation on surface sensitive properties may be measured indpendently, it is important to understand the microstructural evolution leading to these changes. Analytical electron microscopy provides a useful tool for characterizing the microstructures produced in terms of solute concentration profiles, second phase formation, lattice damage, crystallinity of the implanted layer, and annealing behavior. Such analyses allow correlations to be made with theoretical models, property measurements, and results of complimentary techniques.

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