直接电化学还原钛合金固体氧化物熔盐

Chem. Rev., 2013, 113 (5), pp 2863–2886
Chem. Soc. Rev., 2014, 43, 3215-3228
The conventional methods
Carbothermic methode
TiO 2 1 N 2 ( g ) 2C ( s ) TiN ( s ) 2CO ( g ) 2 TiN ( s ) Ti( 熔融Sn 中) 1 N2 2
Metallothemic methode （Kroll）
T iCl4 2Mg 2MgCl2 T i
TiCl4 electrolysis The high cost
Disadvantages
Complex process High energy consumption Serious environmental pollution
Fig. 5. The SEM images of the products completely electrolyzed (electrolyzed for 5 h) with different starting stoichiometries: (a) TiO2:SiO2 = 3:1; (b) TiO2:SiO2 = 5:3; (c) TiO2:SiO2 = 5:4; (d) TiO2:SiO2 = 1:1; (e) TiO2:SiO2 = 1:2.
• Equilibrium • Current increasing • Current decline
Fig. 4. The current–time curves of the electrolysis for different time, TiO2:SiO2 = 5:3, the insert is the initial part of the current–time curve.
Direct electrochemical reduction of solid oxide to Ti/alloy in molten salt
朱诗悦 李一航 王亚光 张璐 宦道明 程涛 夏飞 倪 堃 杨明晔 武煜森
Baidu Nhomakorabeai
Advantages • • • • • • high strength & lightweight good conductivity non- magnetic high-temperature resistance biocompatibility resistance to corrosion Applications • Aeroplanes & military industry • Sports equipment • Bone substitute in medical implants • Increasing electrode reaction rate in electrochemical systems (porous microstructure )
TiO2 2 xe' TiO2-x xO2
(Magnelli phases)
NATURE |VOL 407 | 21 SEPTEMBER 2000
Advatages of FFC
Metal Alloy Functional oxide
Nanostructured semiconductors
Fig. 2. XRD patterns of the mixed powders (TiO2:SiO2 = 5:3) electrolyzed for different times. (a) 1 h; (b) 3 h; (c) 5 h.
Fig. 3. SEM images of the cross-section of a mixed powder pellet (TiO2:SiO2 = 5:3) electrolyzed for 3 h. (a) The whole pellet; (b) the inner part of the pellet; (c) the boundary of inner and outer parts; (d) the outer part. The inset plots in (b) and (d) are the EDX spectra measured over the image areas, respectively.
(clean, efficient, affordable)
Alloy
+
_
X. Zou et al. / Electrochimica Acta 55 (2010) 5173–5179
TiO2:SiO2=5:3 950℃ 2.5V/0.5h 4.0V/1~5h
Fig. 1. The phase diagram of Ti–Si system
Thank you! Happy new year!
二氧化钛熔盐电解钛的实验及机理研究
Direct electrochemical reduction
OS (Ono-Suzuki) process
FFC-Cambridge process
o G Eo nF
FFC
• Temperature:850~950 ℃ • Applied voltage: 3.0~3.2 V
conclusion
FFC-Cambridge process
is a new highly efficient and environment-friendly method to reduce solid oxide into metal. It developing a new systems to produce a wide range of wellknown alloys. The reaction processes are characterised during electrolysis. The initial composition of the precursor will effect the final composition and microstructure of final products .