Study on Preparation of Ti Powder by Self-Propagating High-Temperature Synthesis (SHS) with Magnesiothermit Reductive Process

2008 ◽  
Vol 575-578 ◽  
pp. 1086-1092
Author(s):  
Peng Lin Zhang ◽  
Tian Dong Xia ◽  
Guo Dong Zhang ◽  
Li Jing Yan
Keyword(s):  
Reaction Rate ◽  
Combustion Temperature ◽  
Combustion Process ◽  
Green Compact ◽  
Reaction Products ◽  
Technological Parameters ◽  
Solid Reaction ◽  
Temperature Synthesis ◽  
High Temperature Synthesis ◽  
Ti Powder

The combustion process of Mg-TiO2 system was preliminarily investigated from three aspects of thermodynamics, reaction kinetics and the technological parameters. The result indicates that the adiabatic temperature of Mg-TiO2 system is between 2060K and 2140K because the major existent modalities of TiO2 is the rutile and anatase, this meets the empirical criterion that the SHS reaction will be self-sustaining; The solid-solid reaction occurs at about 767K; Ti powders can be produced only when the ratio between Mg and TiO2 arrives at 2.9:1; The higher the vacuum, the more complete the reaction; The combustion temperature arrives at its peak when the pressure of green compact arrives at 250MPa; the velocity of the combustion wave increases with the augmentation of the pressure of green compact. So the proper control of the technological parameters can change the reaction temperature, reaction rate and the components of reaction products.

Self-propagating high-temperature synthesis of nano-sized titanium carbide powder

2002 ◽  
Vol 17 (11) ◽  
pp. 2859-2864 ◽  
Author(s):  
H. H. Nersisyan ◽  
J. H. Lee ◽  
C. W. Won
Keyword(s):  
Sodium Chloride ◽  
Titanium Carbide ◽  
Combustion Temperature ◽  
Combustion Process ◽  
Carbide Powder ◽  
Primary Carbide ◽  
Temperature Synthesis ◽  
Ultrafine Structure ◽  
High Temperature Synthesis ◽  
Carbon System

The combustion process of a titanium–carbon system with sodium chloride as an inert diluent was investigated. The combustion laws and microstructure of final products according to diluent content were obtained. It was shown that sodium chloride not only decreases combustion temperature but also makes effective protective shells around primary carbide crystals and keeps this ultrafine structure up to the end of combustion. As a result, nano-sized titanium carbide powders were successfully obtained.

Effects of Ti Powder Additions in Melt-SHS Process on the Performance of Al-Ti-B Grain Refiner Alloys

2016 ◽  
Vol 877 ◽  
pp. 121-126
Author(s):  
He Li ◽  
Li Hua Chai ◽  
Zhi Lei Xiang ◽  
Yong Shuang Cui ◽  
Zi Yong Chen
Keyword(s):  
Master Alloy ◽  
Reaction Rate ◽  
Grain Refining ◽  
Grain Refiner ◽  
Temperature Synthesis ◽  
Refining Efficiency ◽  
Strip Shape ◽  
High Temperature Synthesis ◽  
Al Powder ◽  
Ti Powder

Melt-SHS (Self-propagating High-temperature Synthesis) was used for the preparation of Al–5Ti–1B master alloy. The quality ratio of Ti powder/TiO2 in initial powder mixture was varied from 0:1 to 1:0. The AES, XRD and SEM were applied to evaluate the microstructure and phase componet. The results showed that the Al-5Ti-1B master alloy could be successful produced by the reaction of Al powder, TiO2 and H3BO3 in Al melt, while the reaction rate was slow. The microstructure mainly presents the TiAl3 particles with long strip shape. A significant improvement was noted both in reaction rate and in the grain refining efficiency when Ti powder was added to the reactants and the optimized ratio of Ti powder/TiO2 was 2:3. The TiAl3 particles were reduced and the grain refining efficiency turned bad when Ti powder was totally used to supply Ti

scholarly journals Effect of Cu addition and heat treatment self-propagating high temperature synthesis reaction in Al-Ti-C system

2008 ◽  
Vol 40 (2) ◽  
pp. 207-214 ◽  
Author(s):  
Y.X. Li ◽  
J. Hu ◽  
Y.H. Liu ◽  
Z.X. Guo
Keyword(s):  
Heat Treatment ◽  
High Temperature ◽  
Combustion Temperature ◽  
The Self ◽  
Synthesis Reaction ◽  
Reaction Products ◽  
Temperature Synthesis ◽  
Rigid Framework ◽  
High Temperature Synthesis ◽  
Al2cu Phase

Effect of Cu addition and heat treatment on the self-propagating high temperature synthesis reaction have been investigated. The results show that Cu reacts with Al to form Al2Cu phase. With the addition of Cu, the combustion temperature of the system decreases and the porosity of the products is reduced, the size of TiC particulate decreases in the SHS reaction products. Specially, when heat treatment is carried out for the sintering products at 800 ?C, the rigid framework (sintering neck) between TiC particles was formed.

scholarly journals Self-propagating High-temperature Synthesis of Materials Based on Tungsten Carbide for One-Pot Hydrolysis-Hydrogenolysis of Cellulose Into Ethylene Glycol and 1,2-Propylene Glycol

2019 ◽  
pp. 269-281
Author(s):  
Nikolay V. Gromov ◽  
Тatiana B. Medvedeva ◽  
Ivan А. Lukoyanov ◽  
Alekasandr А. Zhdanok ◽  
Vladimir А. Poluboyarov ◽  
...  
Keyword(s):  
High Temperature ◽  
Ethylene Glycol ◽  
Tungsten Carbide ◽  
Propylene Glycol ◽  
Reaction Rate ◽  
Total Yield ◽  
Temperature Synthesis ◽  
One Pot ◽  
Catalytic Systems ◽  
High Temperature Synthesis

Catalytic systems based on tungsten carbide (WnC) containing mainly W2C were obtained by the method of self-propagating high-temperature synthesis from a mechanochemically activated mixture of tungsten oxide, metallic magnesium, carbon black and CaCO3. The phase composition of the formed materials was shown to depend on the amount of CaCO3. The catalytic properties of the materials were tested in the hydrolysis-hydrogenation of cellulose to ethylene glycol (EG) and 1,2-propylene glycol (PG). It was established that in the presence of WnC the main products of the reaction were EG and PG with a ratio of PG/EG – 1.5-1.8. The deposition of nickel nanoparticles on the WnC surface increased the reaction rate and product yields. The maximum total yield of diols was 47.1 mol. %.

Composite materials based on Al2O3‒SiC‒TiB2 obtained by SHS extrusion and their hightemperature annealing

2021 ◽  
pp. 51-55
Author(s):  
A. P. Chizhikov ◽  
A. S. Konstantinov ◽  
M. S. Antipov ◽  
P. M. Bazhin ◽  
A. M. Stolin
Keyword(s):  
Heat Treatment ◽  
High Temperature ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Pressing Pressure ◽  
Technological Parameters ◽  
Temperature Synthesis ◽  
Shs Extrusion ◽  
High Temperature Synthesis ◽  
Before And After

As a result of the combination of the processes of selfpropagating high-temperature synthesis (SHS) and shear high-temperature deformation, realized in the method of SHS-extrusion, ceramic rods based on Al2O3‒SiC‒TiB2 were obtained. The influence of technological parameters of the process (delay time, pressing pressure) on the length of the obtained rods has been studied. The obtained materials were annealed in the range 1000‒1300 °C, and the microstructure and phase composition of the materials were studied before and after heat treatment.

Effect of Ti Contents on the Microstructure and Mechanical Properties of Ni˗Al˗Ti System

2020 ◽  
Vol 991 ◽  
pp. 24-29
Author(s):  
Dhimas Wicaksono ◽  
Xiao Meng Zhu ◽  
Mohammad Sukri Mustapa ◽  
Sulis Yulianto ◽  
Ahmad Yunus Nasution ◽  
...  
Keyword(s):  
Vickers Microhardness ◽  
Combustion Process ◽  
Intermetallic Phases ◽  
External Heat ◽  
Temperature Synthesis ◽  
Mixed Powder ◽  
External Heat Source ◽  
High Temperature Synthesis ◽  
Ti Content ◽  
Heat Released

In this work, a ternary system prepared by Ni-Al-Ti mixed powder was synthesized using self-propagation high-temperature synthesis (SHS) process. The weight of the reactant was varied using 3%, 10%, 20% and 30% of the Ti content. The mixtures were compressed in a steel die to form compacted pellets, and subsequently ignited using an external heat source to initiate the combustion process. The synthesized products were characterized using SEM, EDS, and XRD, whereas the mechanical property of the product was measured using a Vickers microhardness test. The identification of the formed phase indicates that Ni-Al, Ti-Al and Ti-Ni systems were formed during the reaction. An increase of Ti content from 3% to 10% improves the density of the synthesized product. Further increase of Ti content to 20% results in the generation of cracks. The addition of Ti with 30% leads to the formation of a porous product. The heat released by the SHS process due to the formation of several intermetallic phases was responsible for the formation of defect products. The highest hardness of the product was achieved in the product prepared by 20% Ti content. However, the higher Ti content than 20% results in hardness reduction. This work shows that the content of 10% of Ti produced a dense and hard product.

Combustion synthesis of mechanically activated powders in the Nb–Si system

2002 ◽  
Vol 17 (8) ◽  
pp. 1992-1999 ◽  
Author(s):  
Filippo Maglia ◽  
Chiara Milanese ◽  
Umberto Anselmi-Tamburini ◽  
Stefania Doppiu ◽  
Giorgio Cocco
Keyword(s):  
Mechanical Activation ◽  
Single Phase ◽  
Milling Time ◽  
Combustion Process ◽  
Temperature Wave ◽  
The Self ◽  
Temperature Synthesis ◽  
High Temperature Synthesis ◽  
Niobium Silicides ◽  
Reactant Powder

The effect of the mechanical activation of the reactants on the self-propagating high-temperature synthesis (SHS) of niobium silicides was investigated. SHS experiments were performed on reactant powder blends of composition Nb:Si = 1:2 and Nb:Si = 5:3 pretreated for selected milling times. A self-sustaining reaction could be initiated when a sufficiently long milling time was employed. At short milling times, the reactions self-extinguished or propagated in an unsteady mode. Combustion peak temperature, wave velocity, and product composition were markedly influenced by the length of the milling treatment. Single-phase products could be obtained for sufficiently long milling times. Observation of microstructural evolution in quenched reactions together with isothermal experiments allowed clarification of the mechanism of the combustion process and the role played by the mechanical activation of the reactants.

Superfast Sintering of Nanocrystalline Y2O3 Ceramics

2009 ◽  
Vol 66 ◽  
pp. 100-103 ◽  
Author(s):  
Xia Zheng ◽  
Zheng Yi Fu ◽  
Jin Yong Zhang ◽  
Wei Min Wang ◽  
Hao Wang ◽  
...  
Keyword(s):  
High Temperature ◽  
Heating Rate ◽  
Grain Growth ◽  
Combustion Temperature ◽  
Applied Pressure ◽  
The Self ◽  
Temperature Synthesis ◽  
High Temperature Synthesis ◽  
Chemical Furnace ◽  
Maximum Combustion Temperature

Dense nanocrystalline Y2O3 ceramics without grain growth have been successfully obtained by a new method, which is based on the self-propagating high temperature synthesis and quick pressing. A suitable self-propagating system with a maximum combustion temperature of 1350 °C and a heating rate of 1300 °C/min was chosen as a chemical furnace to supply the heat to densify nanocrystalline Y2O3. Dense samples without grain growth were obtained when the applied pressure was 120 MPa.

scholarly journals The Influence of Thermal Dilution on the Microstructure Evolution of Some Combustion-Synthesized Refractory Ceramic Composites

Crystals ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 59
Author(s):  
Sofiya Aydinyan ◽  
Suren Kharatyan ◽  
Irina Hussainova
Keyword(s):  
Combustion Temperature ◽  
Heterogeneous Media ◽  
Combustion Process ◽  
Combustion Products ◽  
Ceramic Composites ◽  
High Yield ◽  
High Temperature Synthesis ◽  
High Level ◽  
Refractory Ceramics ◽  
Thermal Dilution

Modeling the self-sustained high-temperature synthesis (SHS) reaction via thermal dilution and transformation of the reaction heterogeneous media into a moderate exothermic one has unlimited potential for designing inorganic powders of a certain morphology beneficial for advanced consolidation. Thermal/inert dilution of the high-exothermic mixtures leads to the fluent decrease of both the combustion temperature and velocity, thus allowing to tailor the thermal regime of the combustion process, therewith contributing to high yield of reaction and governing the microstructural features of the combustion products. In the current review, we shed on light on the possibilities of this effective strategy to control the thermal behavior of the SHS process for the preparation of applicable powder precursors for the subsequent successful sintering. Since the SHS process of some refractory ceramics (MoSi2, TiB2, TiC, etc.) involves a relatively violent reaction rate and high combustion temperature, achieving a high level of microstructure control in these systems is often challenging. The challenge was tackled with a thermal dilution approach, attaining considerable enhancement in the homogeneity among phases with an increase of diluent content along with microstructure refinement.

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