Effect of CaF2 in Precursors on Steel Pipe Lined Fe-Al Intermetallic-TiB2-Al2O3 Composite Coating by Centrifugal-SHS Process

2012 ◽  
Vol 488-489 ◽  
pp. 468-472 ◽  
Author(s):  
Pajaree Kerdkool ◽  
Sutham Niyomwas

Steel pipe lined Fe-Al intermetallic-TiB2-Al2O3composite were prepared by centrifugal-self-propagating high temperature synthesis (centrifugal-SHS) process from FeTiO3, B2O3, Fe2O3, Al and CaF2as raw materials. The standard Gibbs energy minimization method was used to calculate the equilibrium compositions of the reacting species. The effect of adding CaF2to the precursors on the result product were investigated. The phase separation between less porosity Fe-Al intermetallics-TiB2with Al2O3layer were affected greatly by adding CaF2. The phase compositions and morphology were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM) couple with energy dispersive X-ray (EDX), respectively.

2018 ◽  
Vol 280 ◽  
pp. 121-126
Author(s):  
Si Thu Myint Maung ◽  
Tawat Chanadee ◽  
Sutham Niyomwas

Intermetallic alloy of tungsten silicide (WSi2-W5Si3) was synthesized by self-propagating high temperature synthesis (SHS) from the reactant of tungsten oxide (WO3) and silicon lump (Si) using magnesium (Mg) as fuel. The standard Gibbs energy minimization method was used to calculate the equilibrium composition of the possible reacting species. The as-SHS products were characterized by X-ray diffraction (XRD) technique. The magnesiothermic reaction process successfully synthesized dense of WSi2-W5Si3intermetallic alloy. According to the experimental results, it can be proposed that the reaction also promotes the phase separation between alloy and oxide slag of the product.


2012 ◽  
Vol 488-489 ◽  
pp. 305-309 ◽  
Author(s):  
Kunyaporn Tapsuan ◽  
Sutham Niyomwas

The Fe3Al-TiB2-Al2O3 composite has been prepared by self-propagating high-temperature synthesis (SHS) from FeTiO3-B2O3-Al system. The standard Gibbs energy minimization method was used to calculate the equilibrium compositions of the reacting species. The reactions were carried out in a SHS reactor under static argon gas at the pressure of 0.5 MPa. The effects of Al molar ratio of 4, 4.33 and 5 mole on the results product were investigated. The composition and microstructure of SHS products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). The optimum result of Fe3Al intermetallics phase was obtained when using 4.33 mole of Al.


2012 ◽  
Vol 626 ◽  
pp. 1-5
Author(s):  
Sutham Niyomwas

The TiB2-Al2O3 porous composites were obtained in situ by self-propagating high temperature synthesis (SHS) of TiO2-B2O3-Al System. The reaction was carried out in a SHS reactor under static argon gas at the pressure of 0.5 MPa. The standard Gibbs energy minimization method was used to calculate the equilibrium composition of the reacting species. The effects of increasing aluminum mole ratio to the precursor mixture of TiO2, B2O3 and Al were investigated. XRD and SEM analyses indicate complete reaction of precursors to yield TiB2-Al2O3 as product composite


2014 ◽  
Vol 32 (4) ◽  
pp. 696-701 ◽  
Author(s):  
Hong-Yan Sun ◽  
Xin Kong ◽  
Wei Sen ◽  
Zhong-Zhou Yi ◽  
Bao-Sen Wang ◽  
...  

AbstractEffect of different Sn contents on combustion synthesis of Ti2SnC was studied using elemental Ti, Sn, C and TiC powders as raw materials in the Ti-Sn-C and Ti-Sn-C-TiC system, in which the molar ratio of Ti/C was set as 2:1. The reaction mechanism for the formation of Ti2SnC was also investigated. The results showed that the amount of Ti2SnC in combustion products firstly increased with increasing of Sn content (0.6 to 0.8 mol), and then decreased with further increasing of Sn content (1.0 to 1.2 mol). Upon addition of 15 % TiC instead of Ti and C, the optimum addition of Sn decreased to 0.7 mol and a higher purity of Ti2SnC was obtained. The Ti2SnC powders were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD).


2013 ◽  
Vol 748 ◽  
pp. 36-40
Author(s):  
Kunyaporn Tepsuan ◽  
Sutham Niyomwas

The Fe-Al2O3 composite has been prepared by high-frequency induction heated combustion synthesis (HFIHCS) from Fe2O3 and Al powders. The standard Gibbs energy minimization method was used to calculate the equilibrium compositions of the reacting species. The composition and microstructure of HFIHCS products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX).


2015 ◽  
Vol 659 ◽  
pp. 545-549 ◽  
Author(s):  
Saowanee Singsarothai ◽  
Vishnu Rachphet ◽  
Sutham Niyomwas

The Iron-Tungsten boride based composite was coated on the inner surface of steel pipes by centrifugal-self-propagating high-temperature synthesis (centrifugal-SHS) process. The precursors were prepared by a stoichiometric ratio of wolframite mineral (Fe (Mn)WO4), aluminum (Al) and boron oxide (B2O3). Phase composition and microstructure of composite coating were investigated by X-ray diffraction (XRD) and scanning electron microscope (SEM). On this study, depending on the rotation speed, the highest rotation speed (2250 rpm) produced highest micro-hardness of the composite (1699 HV).


2011 ◽  
Vol 415-417 ◽  
pp. 226-231
Author(s):  
Xin Wei

Alumina-Tungsten Carbide (Al2O3-WC) composites were synthesized by self-propagating high temperature synthesis (SHS) from a powder mixture of WO3-C-Al. The reaction was carried out in a SHS reactor under static argon gas at a pressure of 0.5 MPa. The standard Gibbs energy minimization method was used to calculate the equilibrium composition of the reacting species. The effects of carbon mole ratio in precursor mixture and diluents of NaCl and Al2O3 on the Al2O3-WC conversion were investigated using X-ray diffraction and scanning electron microscope technique. The as-synthesized products of Al2O3-WC2-WC powders were concurrently formed and the reduction of W2C phase was found when added diluents in precursors.


Metals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 873
Author(s):  
Chun-Liang Yeh ◽  
Chih-Yao Ke

The fabrication of intermetallic/ceramic composites by combustion synthesis in the mode of self-propagating high-temperature synthesis (SHS) was investigated in the Al–Ni–Ti system with the addition of B4C. Two reaction systems were employed: one was used to produce the composites of xNiAl–2TiB2–TiC with x = 2–7, and the other was used to synthesize yNi3Al–2TiB2–TiC with y = 2–7. The reaction mechanism of the Al–Ni–Ti system was strongly influenced by the presence of B4C. The reaction of B4C with Ti was highly exothermic, so the reaction temperature and combustion velocity decreased due to increasing levels of Ni and Al in the reactant mixture. The activation energies of Ea = 110.6 and 172.1 kJ/mol were obtained for the fabrication of NiAl- and Ni3Al-based composites, respectively, by the SHS reaction. The XRD (X-ray diffraction) analysis showed an in situ formation of intermetallic (NiAl and Ni3Al) and ceramic phases (TiB2 and TiC) and confirmed no reactions taking place between Ti and Al or Ni. The microstructure of the product revealed large NiAl and Ni3Al grains and small TiB2 and TiC particles. With the addition of TiB2 and TiC, the hardness of NiAl and Ni3Al was considerably increased and the toughness was also improved.


2012 ◽  
Vol 626 ◽  
pp. 138-142
Author(s):  
Saowanee Singsarothai ◽  
Vishnu Rachpech ◽  
Sutham Niyomwas

The steel substrate was coated by Fe-based composite using self-propagating high-temperature synthesis (SHS) reaction of reactant coating paste. The green paste was prepared by mixing precursor powders of Al, Fe2O3and Al2O3. It was coated on the steel substrate before igniting by oxy-acetylene flame. The effect of coating paste thickness and the additives on the resulted Fe-based composite coating was studied. The composite coating was characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM) couple with dispersive X-ray (EDS).


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