Thermodynamic Investigation of Ti-H System by Molten Salt Electrochemical Technique

2001 ◽  
Vol 148 (1) ◽  
pp. E38 ◽  
Author(s):  
Tokujiro Nishikiori ◽  
Toshiyuki Nohira ◽  
Yasuhiko Ito
Keyword(s):  
Molten Salt ◽  
Electrochemical Technique ◽  
Thermodynamic Investigation

scholarly journals Direct oxygen removal technique for recycling titanium using molten MgCl2salt

2016 ◽  
Vol 190 ◽  
pp. 109-126 ◽  
Author(s):  
Toru H. Okabe ◽  
Yuki Hamanaka ◽  
Yu-ki Taninouchi
Keyword(s):  
Molten Salt ◽  
Chemical Potential ◽  
Oxygen Removal ◽  
Electrochemical Technique ◽  
High Grade ◽  
Constant Voltage ◽  
Graphite Electrodes ◽  
Kroll Process ◽  
Deoxidizing Agent ◽  
Removal Technique

Deoxidation of Ti, or direct removal of O dissolved in metallic Ti, is known to be extremely difficult when Mg is used as the deoxidizing agent. This difficulty arises because the chemical potential of O2,pO2, under Mg/MgO equilibrium is high (approximately 10−41atm at 1200 K) and is equivalent to that of Ti containing ∼2 mass% O at 1200 K. Therefore, when deoxidizing Ti to the commercial level of high-grade pure Ti (below 0.05 mass% O) using an Mg reductant at 1200 K, the activity of the reaction product MgO (aMgO) must be decreased to below ∼0.025, which is difficult in practice. In this study, the removal of O in Ti in molten MgCl2salt using an electrochemical technique was examined at ∼1173 K with the objective of obtaining Ti containing less than 0.05 mass% O. Ti samples and graphite electrodes immersed in molten MgCl2served as the cathode and anode, respectively. A constant voltage was applied between the electrodes using an external DC source. Molten MgCl2was employed to produce the deoxidizing agent Mg and to facilitate deoxidation of Ti by decreasing the activity of the reaction product MgO. By applying a voltage of approximately 3.1 V between the electrodes, the chemical potential of Mg in the molten MgCl2was increased at the surface of the Ti cathode, and the Ti samples were deoxidized. The resulting O species, mainly formed O2−dissolved in the molten MgCl2, was removed from the molten salt by reacting with the C anode to form CO (or CO2) gas. Ti wires containing 0.12 mass% O were deoxidized to less than 0.02 mass% O. In some cases, the O concentration in the Ti samples was reduced to the level of 0.01 mass%, which cannot be accomplished using the conventional Kroll process. The possible application of this deoxidation technique to practical industrial recycling processes is discussed.

High Temperature Corrosion of Spray-Atomized FeAl (40at.%) Based Alloys:Immersed in a Molten Salt Mixture of V2O5-Na2SO4

1998 ◽  
Vol 552 ◽  
Author(s):  
M. Amaya ◽  
E. J. Lavernia ◽  
L. Martinez
Keyword(s):  
Weight Loss ◽  
High Temperature ◽  
Molten Salt ◽  
Passive Layer ◽  
High Temperature Corrosion ◽  
Electrochemical Technique ◽  
Salt Mixture ◽  
Protective Oxide ◽  
Metal Base ◽  
Temperature Range

ABSTRACTWe studied the high temperature corrosion of spray atomized and deposited FeAl40at% based intermetallic alloys immersed in a molten salt mixture of 80%V2O 5+20%Na2SO4 (wt%) over the temperature range of 600–900°C. Experiments were realized by the weight loss method and the potentiodynamic polarization electrochemical technique in three different samples: FeA140at%, FeA140+0.lat%B and FeA140+0.lat%B+10at%A12O3. Measurements of weight loss and corrosion current density as a function of the molten salts temperature were obtained and discussed in terms of the passive layer morphology and corrosion products formed during the tests. It was found that the iron aluminide doped with boron and reinforced with alumina particulate was more corrosion resistant in the test temperature range. The weight loss experiments revealed that at 700°C all alloys developed maximum corrosion rate. This behavior was related with the dissolution of protective oxide layer on metal base due the formation of vanadate phases which are highly corrosive at this temperature.

Kinetic Investigation of the Ti-H System by a Molten Salt Electrochemical Technique

2001 ◽  
Vol 148 (3) ◽  
pp. E127 ◽  
Author(s):  
Tokujiro Nishikiori ◽  
Toshiyuki Nohira ◽  
Yasuhiko Ito
Keyword(s):  
Molten Salt ◽  
Electrochemical Technique ◽  
Kinetic Investigation

Thermodynamic Evaluation of Ti-H System at Medium-Range Temperatures by Molten Salt Electrochemical Technique

2003 ◽  
Vol 150 (7) ◽  
pp. E355 ◽  
Author(s):  
Takeo Kasajima ◽  
Tokujiro Nishikiori ◽  
Toshiyuki Nohira ◽  
Yasuhiko Ito
Keyword(s):  
Molten Salt ◽  
Electrochemical Technique ◽  
Thermodynamic Evaluation ◽  
Medium Range
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