Synthesis of Nanostructure MoSi2 Powder by Mechanically Assisted Self-Propagating High-Temperature Synthesis

2010 ◽  
Author(s):  
R. Meshkizadeh ◽  
H. Abdollahpour ◽  
A. Honarbakhsh-Raouf
Keyword(s):  
High Temperature ◽  
Ball Milling ◽  
Powder Mixture ◽  
Combustion Temperature ◽  
Combustion Method ◽  
Temperature Synthesis ◽  
Mixed Powder ◽  
Powder Mixtures ◽  
High Temperature Synthesis

Nanostructured MoSi2 powder has been successfully synthesized by Ball milling of Mo and Si powder mixtures and subsequent self-propagating high-temperature synthesis (SHS) process. It was observed that in comparison with the normally mixed powder, it could be easily ignited and higher combustion temperature was achieved. Based on XRD and SEM, it was confirmed that nanostructure MoSi2 powder could be prepared through self propagating combustion method from the mechanical activated powder mixture.

Combustion Synthesis of (Ti,V)2AlC Solid Solutions

2014 ◽  
Vol 909 ◽  
pp. 19-23
Author(s):  
Chun Liang Yeh ◽  
Wen Jung Yang
Keyword(s):  
High Temperature ◽  
Solid Solutions ◽  
Reaction Front ◽  
Combustion Temperature ◽  
Product Formation ◽  
Front Velocity ◽  
Temperature Synthesis ◽  
Powder Mixtures ◽  
Substitution Site ◽  
High Temperature Synthesis

(Ti,V)2AlC solid solutions with Al2O3 addition were produced by solid state combustion involving aluminothermic reduction in the mode of self-propagating high-temperature synthesis (SHS). Starting materials included Ti/V2O5/Al/Al4C3 and TiO2/V2O5/Al/Al4C3 powder mixtures. Attempts were made to obtain (Ti1-xVx)2AlC with a broad substitution percentage. Combustion exothermicity was increased by increasing V2O5 for the yield of a higher proportion of V at the substitution site, which not only increased the combustion temperature and reaction front velocity, but also facilitated the evolution of (Ti,V)2AlC. The Ti-containing samples showed higher reaction exothermicity and better product formation than those adopting TiO2. As a result, (Ti1-xVx)2AlC with x from 0.2 to 0.8 was produced from the samples composed of the Ti/V2O5/Al/Al4C3 mixture. The (Ti,V)2AlC/Al2O3 composites synthesized in this study exhibited a laminated microstructure with closely-stacked (Ti,V)2AlC slabs of about 0.30.8 μm.

scholarly journals Al-Ti-B4C materials obtained by high-temperature synthesis and used as a master-alloy for aluminum

2018 ◽  
Vol 243 ◽  
pp. 00010 ◽  
Author(s):  
Ilya Zhukov ◽  
Vladimir Promakhov ◽  
Yana Dubkova ◽  
Alexey Matveev ◽  
Mansur Ziatdinov ◽  
...  
Keyword(s):  
High Temperature ◽  
Burning Rate ◽  
Powder Mixture ◽  
Pure Aluminum ◽  
Al Alloy ◽  
Initial Powder ◽  
Temperature Synthesis ◽  
Al Content ◽  
High Temperature Synthesis ◽  
Al Powder

The paper presents microstructure, composition, and burning rate of Al alloy produced by high-temperature synthesis (SHS) from powder mixture Al-Ti-B4C with different concentration of Al powder. It has been established that the phase composition of materials obtained at gas-free combustion includes TiB2, Al, and TiC. It is shown that Al content growth powder in initial Al-Ti- B4C mixture from 7.5 to 40 wt.% reduces the burning rate of the powder from 9*10-3 to 1.8*10-3 m/s. For the system consisting of 60 wt.% of (Ti + B4C) and 40 wt.% of Al there is the increase in the porosity of the compacted initial powder mixture from 30 to 51 and reduction in the burning rate from 1.8 * 10-3 to 1 * 10-3 m/s. The introduction of 0.2 wt.% of the obtained SHS materials into the melt of pure aluminum causes reduction of the grain size of the resulting alloy from 1200 to 410 μm.

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.

Structure Formation during High-Temperature Synthesis in an Activated Ti + Al Powder Mixture

2019 ◽  
Vol 55 (11) ◽  
pp. 1097-1103
Author(s):  
V. Yu. Filimonov ◽  
M. V. Loginova ◽  
A. V. Sobachkin ◽  
S. G. Ivanov ◽  
A. A. Sitnikov ◽  
...  
Keyword(s):  
High Temperature ◽  
Structure Formation ◽  
Powder Mixture ◽  
Temperature Synthesis ◽  
High Temperature Synthesis ◽  
Al Powder

Synchrotron in situ studies of mechanical activation treatment and γ-radiation impact on structural-phase transitions and high-temperature synthesis parameters during the formation of γ-(TiAl) compound

2019 ◽  
Vol 26 (5) ◽  
pp. 1671-1678 ◽  
Author(s):  
Marina Loginova ◽  
Alexey Sobachkin ◽  
Alexander Sitnikov ◽  
Vladimir Yakovlev ◽  
Valeriy Filimonov ◽  
...  
Keyword(s):  
High Temperature ◽  
Mechanical Activation ◽  
Thermal Explosion ◽  
Powder Mixture ◽  
Maximum Temperature ◽  
Γ Irradiation ◽  
Temperature Synthesis ◽  
High Temperature Synthesis ◽  
The Impact

In situ synchrotron studies of structure and phase formation dynamics in mechanically activated (t = 7 min, power density 40 g) and mechanically activated with subsequent irradiation by γ-quanta 60Co powder mixture (Ti 64 wt% + Al) during high-temperature synthesis by the method of thermal explosion using induction heating are described. In situ high-temperature synthesis was carried out on the created experimental complex adapted for synchrotron X-ray diffraction methods. The sequence of formation and time–temperature interval of the metastable and main phases were determined. The impact of preliminary mechanical activation and of γ-irradiation on the macrokinetic parameters of the synthesis were studied experimentally in situ. It has been established that the impact of γ-irradiation on the mechanically activated powder mixture of the composition Ti 64 wt% + Al leads to a change in the thermal parameters of combustion: the maximum synthesis temperature and the burning rate decrease. The heating rate for the non-irradiated mixture is 204.8 K s−1 and that for the irradiated mixture is 81.6 K s−1. The dependences of mass fractions of the synthesized compounds on time and temperature were calculated from the stage of preheating until completion of the thermal explosion. A single-phase equilibrium product of the composition γ-(TiAl) is formed in γ-irradiated mechanically activated mixture when the system reaches maximum temperature. The synthesized product of the mechanically activated mixture without γ-irradiation contains 72% γ-(TiAl); TiAl3 (26%) and residual Ti (2%) are also observed.

Fabrication of BN-AlN-TiB2 Compound Conductive Ceramics by Self-Propagating High Temperature Synthesis and Hot Isostatic Pressing

2007 ◽  
Vol 336-338 ◽  
pp. 786-789 ◽  
Author(s):  
Li Juan Zhou ◽  
Yong Ting Zheng ◽  
Shan Yi Du
Keyword(s):  
High Temperature ◽  
Composition Dependence ◽  
Bending Strength ◽  
Hot Isostatic Pressing ◽  
Microstructural Analysis ◽  
Temperature Synthesis ◽  
Powder Mixtures ◽  
Isostatic Pressing ◽  
High Temperature Synthesis ◽  
Conductive Ceramics

BN-AlN-TiB2 compound conductive ceramics from powder mixtures of BN, Al, and TiB2 was fabricated by self-propagating high temperature synthesis (SHS) and hot isostatic pressing (HIP). The powder mixtures were shaped by isostatic cool pressing at 5-10MPa and the combustion reaction was carried at 100-200 MPa N2 by an ignitor. XRD experiments confirmed that the reaction was complete and only AlN, BN and TiB2 were detected. Optical microscopy as well as SEM with an electron probe microanalysis was used for microstructural analysis and revealed a relatively uniform distribution of particulates. The temperature-dependence and composition-dependence of the electrical resistivity of BN-AlN-TiB2 ceramics were studied. The results showed that the optimum composition was 5-10wt% BN, 30-55wt% Al and 60-40wt% TiB2, and the products had the density of 90% of the theoretical, resistivity of 80-1000 μ⋅cm and bending strength of 100-200 MPa.

Preparation of (Mo,Nb)Si2 Ternary Alloys by Self−Propagating High−Temperature Synthesis

2011 ◽  
Vol 266 ◽  
pp. 219-222
Author(s):  
Pei Zhong Feng ◽  
Shuai Zhang ◽  
Xiao Hong Wang ◽  
Wei Sheng Liu ◽  
Jie Wu
Keyword(s):  
High Temperature ◽  
Flame Front ◽  
Propagation Velocity ◽  
Combustion Temperature ◽  
Front Propagation ◽  
Ternary Alloys ◽  
Combustion Mode ◽  
Temperature Synthesis ◽  
High Temperature Synthesis ◽  
Front Propagation Velocity

An experimental study on the preparation of (Mo,Nb)Si2 ternary alloys was conducted by self-propagating high-temperature synthesis method from elemental powder compacts of different stoichiometries. And the combustion mode, combustion temperature, flame-front propagation velocity and product structure were discussed. The results show that (Mo,Nb)Si2 ternary alloys are characterized by an unsteady state combustion mode with a spiral−trajectory reaction front from top to bottom. The combustion temperature and flame−front propagation velocity decrease with the addition of coarse niobium powder. The combustion temperature and flame-front propagation velocity of MoSi2 are 1629K and 3.13mm/s respectively. However, those of (Mo0.8Nb0.2)Si2 alloy are 1460K and 1.97mm/s. The solid solubility of niobium in MoSi2 is less than 2.5at.%, and the combustion synthesis produce still remains Cllb single-phase structure in (Mo1-x,Nbx)Si2(x<0.075) sample. The C40-type structure appears in (Mo0.925,Nb0.075)Si2 compact and the intensity of diffraction peaks of C40-type phase gradually reinforces with the increase of niobium content. Combustion synthesis is an effective technology for producing (Mo,Nb)Si2 ternary alloys.

EFFECT OF Al CONTENT ON THE COMBUSTION SYNTHESIS OF (TiB2-Al2O3)/Al PRODUCTS FROM AN Al-TiO2-B2O3 SYSTEM

2010 ◽  
Vol 24 (15n16) ◽  
pp. 3203-3208
Author(s):  
LEI ZHAN ◽  
PING SHEN ◽  
QICHUAN JIANG
Keyword(s):  
High Temperature ◽  
Delay Time ◽  
Combustion Temperature ◽  
Ignition Delay Time ◽  
The Self ◽  
Temperature Synthesis ◽  
Al Content ◽  
High Temperature Synthesis ◽  
Maximum Combustion Temperature ◽  
Opposite Tendency

The effect of Al content on the self-propagating high-temperature synthesis (SHS) reaction among Al , TiO 2 and B 2 O 3 was experimentally investigated. The Al content plays an important role in controlling the reaction behaviors. With the increase in reactant Al , the maximum combustion temperature decreases, the propagating wave velocity first increases and then decreases, while the ignition delay time shows an opposite tendency. More importantly, the increase of the Al content in the reactants has an insignificant effect on the phase constitutions of the synthesized products but reduces the size of the synthesized TiB 2 particles.

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