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.

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.

Reaction mechanism of self-propagating high-temperature synthesis reaction in the Ni–Ti–B4C system

2008 ◽  
Vol 23 (9) ◽  
pp. 2519-2527 ◽  
Author(s):  
Y.F. Yang ◽  
H.Y. Wang ◽  
R.Y. Zhao ◽  
Y.H. Liang ◽  
Q.C. Jiang
Keyword(s):  
High Temperature ◽  
Reaction Mechanism ◽  
Intermetallic Compounds ◽  
Eutectic Point ◽  
The Self ◽  
Mutual Diffusion ◽  
Synthesis Reaction ◽  
Temperature Synthesis ◽  
Early Appearance ◽  
High Temperature Synthesis

The SHS reaction in the Ni–Ti–B4C system starts with the formation of Ni–Ti and Ni–B intermetallic compounds from the solid interacted reaction among the reactants and, subsequently, the formation of Ni–Ti and Ni–B liquid at the eutectic point. Meanwhile, some C atoms from the reaction between Ni and B4C can dissolve into Ni–Ti liquid to form TiC. The heat generated from these reactions can promote the mutual diffusion of Ni–Ti–C and Ni–B liquid and simultaneously accelerate the formation of Ni–Ti–C–B liquid. Finally the precipitation of TiC and TiB2 occur when the C and B atoms in the liquid become supersaturated. The addition of Ni not only promotes the occurrence of the self-propagating high temperature synthesis (SHS) reaction by forming Ni–Ti liquid, but also accelerates the SHS reaction by forming Ni–B liquid and dissociative C. The early appearance of dissociative C from the reaction between Ni and B4C causes the formation of TiC prior to that of TiB2.

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.

Phase Formation and Thermodynamic Analysis of Self-propagating High-temperature Synthesis Al–Zr–N System Composites

1998 ◽  
Vol 13 (9) ◽  
pp. 2610-2613 ◽  
Author(s):  
Kexin Chen ◽  
Changchun Ge ◽  
Jiangtao Li
Keyword(s):  
High Temperature ◽  
Melting Point ◽  
Phase Formation ◽  
Combustion Temperature ◽  
Xrd Analysis ◽  
The Self ◽  
Composite Ceramics ◽  
Temperature Synthesis ◽  
High Temperature Synthesis ◽  
The Relationship

The self-propagating high temperature synthesis (SHS) of Al–Zr–N system composite ceramics was investigated in this paper. The melting point of Al was low (Tm = 660 °C), while that of Zr was high (Tm =1855 °C). Therefore, Al will melt and coalesce during reaction, which inhibit diffusion of nitrogen from outside the metal compact to interior due to collapse of the pore openings, while Zr will not melt under the combustion temperature which is lower than its melting point. It will not affect the permeation of nitrogen under the conditions. Accordingly, the ratio of Al and Zr in the initial mixed powders will affect the permeation of nitrogen from outside the sample to the interior, which results in different phase formation of the products. In this study, the relationship between the combustion parameters and the phase formation of the products will be experimentally determined through XRD analysis, and then thermodynamically analyzed.

Solid Phase’s Transformations in Boron Carbide Based Composites during Heat Treatment

2008 ◽  
Vol 138 ◽  
pp. 175-180
Author(s):  
Lembit A. Kommel ◽  
Eduard Kimmari
Keyword(s):  
Heat Treatment ◽  
High Temperature ◽  
Boron Carbide ◽  
Environmental Conditions ◽  
Sliding Wear ◽  
Bending Strength ◽  
Reaction Products ◽  
Temperature Synthesis ◽  
High Temperature Synthesis ◽  
Different Temperatures

Lightweight B4C/Al composites were produced from powders of boron carbide and aluminum by self-propagating high-temperature synthesis (SHS). The effects of postdensification heat treatment at different temperatures and environmental conditions on phase transformations and properties evolution were studied. Heat treatment processing that followed the synthesis was applied using low heating rate in temperature range from 400°C up to 1500°C. An interconnected multiphase (B4C, Al3BC, and c-BN) microstructure was produced in composite as a result of heat treatment at temperatures below 1080°C. The formation of hard and brittle reaction products (AlN, AlB2, Al4C3, and Al8B4C7) at temperatures above 1150°C causes decrease in bending strength and increase in resistance to unlubricated sliding wear.

EFFECT OF BN/Ti RATIO ON THE REACTION SYNTHESIS OF TiB2-TiNx CERAMICS

2009 ◽  
Vol 23 (06n07) ◽  
pp. 1172-1178 ◽  
Author(s):  
LEI ZHAN ◽  
PING SHEN ◽  
QI CHUAN JIANG
Keyword(s):  
High Temperature ◽  
Wave Velocity ◽  
Combustion Temperature ◽  
The Self ◽  
Molar Ratio ◽  
Reaction Synthesis ◽  
Temperature Synthesis ◽  
High Temperature Synthesis

The effects of BN / Ti molar ratio on the self-propagating high-temperature synthesis (SHS) reaction behaviors and final products in the Ti - BN system were experimentally investigated. With an increase in the BN / Ti ratio, the combustion temperature and wave velocity first increase and then decrease with the maximum values displaying at BN / Ti =0.67. A substoichiometric TiN 1- x was obtained for BN / Ti <0.67, and a stoichiometric one was produced for BN / Ti =0.67. Moreover, the microstructure photographs of the products reveal that with the increase of the BN / Ti ratio, the grains of the ceramic phases tend to be finer.

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