Microstructure And Phase Evolution Of Alumina Spinel Self
The Influence of Dopants Particles on the Kinetics of
Evolution of Alumina Ruth Moshe The Influence of Dopants Particles evolving microstructure of alumina and Ni alumina composites has been studied in a range of Mg spinel CaO 6Al 2O 3 CA6 Ca 2Mg 2Al 28O 46 CAM II and alumina grains saturated with Mg and Ca Under these conditions the amount of Ca and Mg in the alumina
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Microstructure evolution in irradiated nuclear materials is a complex process that covers large time and length scales ranging from individual atomic events such as point defect generation
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Alumina rich refractory concretes with added spinel
3 1 Microstructure and phase evolution with temperature The changes in microstructure and phase evolution during the first stages of sintering were mainly due to the calcium aluminate transformations whereas at higher temperatures the change in evolution was clearly due to alumina/magnesia and alumina/dolomite reactions Fig 2a and b show
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Atmosphere and carbon effects on microstructure and phase
In this regards reactive alumina addition to MgO–C refractories has been developed because of its benefits on spinel formation microstructure integrity and improvement of thermo chemical properties The direct reaction of magnesia and alumina to form MA spinel is accompanied by a volume expansion of approximately 5
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Effect of TiO2 Addition in Al2O3 Phase Evolution
List of figures Figure 1 Structure of alumina containing aluminium atoms and oxygen atoms Figure 2 Unit cell of rutile TiO 2 Figure 3 Phase diagram of Al 2 O 3 TiO 2 system Figure 4 Flow chart for work plan Figure 5 Vickers hardness tester and diamond like indentation Figure 6 Schematic of threepoint bending flexural strength test Figure 7 XRD plot of powder of different composition
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Nano treating is a novel concept wherein a low percentage of nanoparticles is used for microstructural control and property tuning in metals and alloys The nano treating of AA7075 was
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Alumina rich refractory concretes with added spinel
3 1 Microstructure and phase evolution with temperature The changes in microstructure and phase evolution during the first stages of sintering were mainly due to the calcium aluminate transformations whereas at higher temperatures the change in evolution was clearly due to alumina/magnesia and alumina/dolomite reactions Fig 2a and b show the mi
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Optimized microstructure with nano‐alumina and its effects
The mechanical properties thermal shock resistance and microstructure evolution of corundum spinel castables with different nano alumina contents were investigated The results show that the addition of nano alumina has advantages on the microstructure evolution and properties of castables An optimum nano alumina amount is 2 wt
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Evolution of an alumina magnesia/self forming spinel
Similar ways have been observed for Al 2 O 3 based products in which fine MgO had been used instead of alumina Thus the evolution of alumina spinel castables has been achieved by two approaches a adding synthetic spinel as an aggregate in an alumina castable and/or b including MgO to the binder phase of the castable
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Investigations of Microstructure and Phase Composition of
A series of slag were fabricated by self shield welding of different flux cored wire The microstructure and phase composition of those slag were investigated by means of metallographic microscope SEM EDX and X ray diffraction respectively The result demonstrated that the slag forming material of TiO2 and Al2O3 tenders to form the framework structure of slag while CaO and MnO2 inclines to
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Kinetic Phase Evolution of Spinel Cobalt Oxide during
Spinel cobalt oxide has been proposed to undergo a multiple step reaction during the electrochemical lithiation process Understanding the kinetics of the lithiation process in this compound is crucial to optimize its performance and cyclability In this work we have utilized a low angle annular dark field scanning transmission electron microscopy method to visualize the dynamic reaction
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Ultra high temperature ceramic composites have been widely investigated due to their improved sinterability and superior mechanical properties compared to monolithic ceramics In this work high entropy boron carbide ceramic/SiC composites with different SiC content were synthesized from multicomponent carbides HfC Mo2C TaC TiC B4C and SiC in spark plasma sintering SPS from
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Effect of SiC on Microstructure Phase Evolution and
The microstructures of HECs containing SiC x = 0 5 1 0 2 0 and 3 0 consist of three distinct phases bright gray and dark marked as 1 2 and 3 in the microstructure of HEC SiC 0 5 in Figure 3 Whereas the microstructure of HEC without addition of SiC HEC SiC 0 show four different contrasts marked as 1 to 4 in HEC SiC 0
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Microstructure and phase evolution of Indian magnesite
To aid development of cost effective sintered spinel as a refractory raw material this paper presents an extensive analysis of microstructure and complex phase evolution of Al rich Mg rich and stoichiometric spinel aggregates derived from Indian magnesite and calcined alumina Pore morphology in Al rich spinel was transformed upon sintering at 1650°C and corundum laths embedded in porous Al rich spinel
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Effects of rare earth oxides additions on microstructure
The phase evolution such as spinel and CA 6 formation in cement bonded spinel forming castables was more complicated Thus the non homogeneous distribution of yttrium and cerium as well as the morphology of CA 6 in alumina magnesia castables was most likely related to the respective interaction mechanism of Y 2 O 3 and CeO 2
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Preparation Microstructure and Mechanical Properties of
The solid wastes fly ash and aluminum dross were used to prepare the low cost high added value product spinel corundum Sialon with an in situ aluminothermic reduction nitridation reaction The effects of varying raw material components and heating temperatures on the phase compositions microstructure bulk density apparent porosity and bending strength of products were investigated
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Effect of Oxide Additives on Phase Evolution and
Four different zirconia toughened alumina added with different pairs of oxides CeO2 TiO2 CuO ZnO and SnO2 were prepared through the co precipitation technique Conventional sintering resulted in relative densities ≥96 Phase analyses of these composites were performed by x ray diffraction Vicker s hardness and tribological behavior of all ZTA composites were studied
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Novel calcium hexaluminate/spinel alumina composites with
Calcium hexaluminate CA6 was incorporated into the matrix of magnesio aluminate spinel alumina MA A via infiltration of a porous preform fabricated from α Al2O3 and MgO powders with a
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Morphology and Phase Evolution in Microwave Synthesized
The phase and microstructure evolution during the reaction were analyzed by differential thermal analysis DTA X ray diffraction XRD and scanning electron microscopy SEM Thermogram of the DTA analysis irrespective of their mole ratio recorded two exothermic peaks one at 1310 o C and another one at 1370 o C
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Effect of SiC on Microstructure Phase Evolution and
Ultra high temperature ceramic composites have been widely investigated due to their improved sinterability and superior mechanical properties compared to monolithic ceramics In this work high entropy boron carbide ceramic/SiC composites with different SiC content were synthesized from multicomponent carbides HfC Mo2C TaC TiC B4C and SiC in spark plasma sintering SPS from
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A review applications of the phase field method in
Microstructure evolution in irradiated nuclear materials is a complex process that covers large time and length scales ranging from individual atomic events such as point defect generation
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Microstructure and phase evolution of alumina–spinel self
Comparison between XRD results of alumina particles the packing of microstructure can increase alumina–spinel refractory castables fired at 1300 8C and considerably which confirms the results of physical and 1500 8C reveals that the nano alumina addition can affect mechanical properties the amount of CA6 phase in the 1300–1500 8C range
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Fracture Energy and Fracture Toughness of In Situ Calcium
1 S Otroj A Daghighi Microstructure and phase evolution of alumina spinel self flowing refractory castables containing nano alumina particles Ceram Int 37 2011 1003–1009
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Microstructural Evolution of NiCoCrAlHfYSi and NiCoCrAlTaY
The chemical composition of NiCoCrAlHfYSi with a suitable particle size deposited using an activated combustion high velocity air fuel AC HVAF spray is a potentially promising process because dense continuous and pure alumina can be formed on the surface of the MCrAlY metallic coatings after isothermal oxidation exposure The NiCoCrAlHfYSi Amdry386 and NiCoCrAlTaY Amdry997
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S Otroj A DaghighiMicrostructure and phase evolution of alumina–spinel self flowing refractory castables containing nano alumina particles Ceram Int 37 3 2011 pp
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Microstructure phase evolution and microwave dielectric properties of Li 2 O and Ga 2 O 3 doped zinc orthosilicate CeramicsSilikáty 61 3 2017 211 through the solution reprecipitation process of the liquid phase sintering According to the theory of liquid phase sintering the dissolved solid diffused through the liquid
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Mechanical and optical properties in precipitated regions
Alumina rich magnesium aluminate spinel MgO nAl 2 O 3 where n=2 was hot pressed and HIPed to produce fully dense single phase material The material was then heat treated in air at 1573 K for up to 20 hours to create a two phase spinel Al 2 O 3 composite The fracture toughness varies from 0 88 to 2 47 MPa√m depending on the
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Microstructure and phase evolution of alumina–spinel self
Hence in this work the effect of addition of nano alumina particles on the microstructure and phase composition of alumina–spinel self flowing refractory castables is investigated For this reason reactive alumina is substituted by nano alumina powder in 0–4 wt range in the castable composition Then castable compositions were fired at various temperatures and physical and mechanical
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tion However the detailed analysis of microstructure and phase evolution by slag penetration has not been addressed sufficiently so far Despite many advantages of in situ spinel bonding expansion difference between spinel and MgO is con sidered as one of the most serious drawbacks which hinders the potential applications of this material To
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Phase Composition and Pore Evolution of Porous
Science of Sintering 48 2016 Corresponding author yanwen wust edu cn doi 10 2298/SOSL UDK 546 46 546 62 622 785 Phase Composition and Pore Evolution of Porous Periclase spinel Ceramics Prepared from Magnesite and Al OH 3 Xiaoli Lin Wen Yan Nan Li The State Key Laboratory of Refractories and Metallurgy Wuhan University of
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TECHNOLOGIES OF ALUMINA MAGNESIA REFRACTORIES
In this article technologies of unburned Al2O3 MgO UAM refractories are demonstrated in terms of microstructure evolution During operation Mg diffuses from MgO to Al2O3 through the liquid phase to form spinel MgAl2O4 network Molten slag tends to penetrate along the voids in the spinel network structure and spinel dissolves in the penetrated slag
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spinel was greatly influenced by variation in composition Similar work by Serry et al 13 describes the effect of various phase compositions and presence of dopants/impurities on the densification of spinel Bulk density obtained after firing at 1700°C was 90 on impure batches compared to pure stoichiometric 85–88 spinel grains
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Effect of spinel kinds on the properties of alumina spinel castables was investigated The results showed that the addition of various kinds of spinels has an effect on the physical and mechanical properties of these refractory castables The reason is that the Al2O3‐rich spinel precipitated Al2O3 and MgO‐rich spinel solid solution and formed secondary spinel In addition stable spinel
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