Titanium based IrO2 +Ta2O5 oxide anodes with different compositions and pyrolysis temperatures were prepared by termodecompoisition method. By using X-ray diffraction (XRD), the structure and texture coefficient of th...Titanium based IrO2 +Ta2O5 oxide anodes with different compositions and pyrolysis temperatures were prepared by termodecompoisition method. By using X-ray diffraction (XRD), the structure and texture coefficient of the coatings, TC(hkl), of IrO2 rutile crystal have been tested. It showed that, the crystallization processes of IrO2 and Ta2O5 in xIrO2 +(100-x) Ta2 O5 (x is in mol%) films affected and confined each other.In the mixed system, IrO2 rutile phase existed as a solid solution with Ta, and attained the maximum solubility when x=70mol%, i.e. for the coating of 70% IrO2 +Ta2O5.For the coatings of low iridium content or at low preparing tem pemture, (110) and (101) pwtered orientations were dominant. However, preferred growth of IrO2 weakened with increasing either iridium content or temperature. Three typical surface morphologies were observed by using scanning electron tnicroscopy(SEM). The crystallite size of the mixed oxide coatings were finest for the the film of 70%IrO2 +30%Ta2O5,and decreased with the pyrolysis tempemture. As the results of the finest crystallite segregating on sudece and the maxitnum solid solubility of Ir and Ta component in deposits, the coatings with the composition of 70%IrO2 +Ta2O5 prepared at 450℃ presented the mdrimutn electrocatalgtic activitg for O2 evolution in 0. 5M H2SO4 solution.UP to 550℃, Ti base suffered to oxidation resulting in decreasing anode conductivity,therefore, coatings performed a low activity.展开更多
Vacuum diffusion bonding of a TiAl based alloy (TAD) to a titanium alloy (TC2) was carried out at 1 273 K for 15～120 min under a pressure of 25 MPa . The kinds of the reaction products and the interface s...Vacuum diffusion bonding of a TiAl based alloy (TAD) to a titanium alloy (TC2) was carried out at 1 273 K for 15～120 min under a pressure of 25 MPa . The kinds of the reaction products and the interface structures of the joints were investigated by SEM, EPMA and XRD. Based on this, a formation mechanism of the interface structure was elucidated. Experimental and analytical results show that two reaction layers have formed during the diffusion bonding of TAD to TC2. One is Al rich α(Ti)layer adjacent to TC2,and the other is (Ti 3Al+TiAl)layer adjacent to TAD,thus the interface structure of the TAD/TC2 joints is TAD/(Ti 3Al+TiAl)/α(Ti)/TC2.This interface structure forms according to a three stage mechanism,namely(a)the occurrence of a single phase α(Ti)layer;(b)the occurrence of a duplex phase(Ti 3Al+TiAl)layer;and(c)the growth of the α(Ti)and (Ti 3Al+TiAl)layers.展开更多
An overview of a severe kind of environmentally-assisted cracking-stress corrosion cracking (SCC) of pressure vessel steel (PVS),such as stainless steel 304, alloy 600,690 and other nickel-based alloys in subcritical ...An overview of a severe kind of environmentally-assisted cracking-stress corrosion cracking (SCC) of pressure vessel steel (PVS),such as stainless steel 304, alloy 600,690 and other nickel-based alloys in subcritical (～300 ℃) aqueous environment was given. The mechanisms of SCC of metals under this inclement surrounding were briefly generalized. Herein,some pragmatic solutions to mitigate the SCC susceptibility and retard its propagation were presented. The titanium and cerium-based inhibitors addition countermeasure was highlighted.展开更多
For developing TiO based imitated gold materials, the wettabilities of Fe and Fe Cr Ni Ti on TiO were studied. The results indicated that the wettabilities of Fe and Fe Cr on TiO were poor, and their wetting angles we...For developing TiO based imitated gold materials, the wettabilities of Fe and Fe Cr Ni Ti on TiO were studied. The results indicated that the wettabilities of Fe and Fe Cr on TiO were poor, and their wetting angles were about 90° at melting point. The wetting angles reduced with the increase of wetting temperature, but the influence of temperature was small. Fe and Fe Cr containing Cr 50% or less could react with TiO on the interface to form Fe 2Ti and Ti 2O 3, but this did not improve the wettability effectively. When Ni Ti was added into Fe Cr alloy, Ni 3Ti was formed on the interface, which can reduce the interface energy, improve the wettability, and prevent the formation of Fe 2Ti and Ti 2O 3. The wetting angles could go down to about 40° when 3% Ni Ti was added to Fe Cr alloy.展开更多
文摘Titanium based IrO2 +Ta2O5 oxide anodes with different compositions and pyrolysis temperatures were prepared by termodecompoisition method. By using X-ray diffraction (XRD), the structure and texture coefficient of the coatings, TC(hkl), of IrO2 rutile crystal have been tested. It showed that, the crystallization processes of IrO2 and Ta2O5 in xIrO2 +(100-x) Ta2 O5 (x is in mol%) films affected and confined each other.In the mixed system, IrO2 rutile phase existed as a solid solution with Ta, and attained the maximum solubility when x=70mol%, i.e. for the coating of 70% IrO2 +Ta2O5.For the coatings of low iridium content or at low preparing tem pemture, (110) and (101) pwtered orientations were dominant. However, preferred growth of IrO2 weakened with increasing either iridium content or temperature. Three typical surface morphologies were observed by using scanning electron tnicroscopy(SEM). The crystallite size of the mixed oxide coatings were finest for the the film of 70%IrO2 +30%Ta2O5,and decreased with the pyrolysis tempemture. As the results of the finest crystallite segregating on sudece and the maxitnum solid solubility of Ir and Ta component in deposits, the coatings with the composition of 70%IrO2 +Ta2O5 prepared at 450℃ presented the mdrimutn electrocatalgtic activitg for O2 evolution in 0. 5M H2SO4 solution.UP to 550℃, Ti base suffered to oxidation resulting in decreasing anode conductivity,therefore, coatings performed a low activity.
文摘Vacuum diffusion bonding of a TiAl based alloy (TAD) to a titanium alloy (TC2) was carried out at 1 273 K for 15～120 min under a pressure of 25 MPa . The kinds of the reaction products and the interface structures of the joints were investigated by SEM, EPMA and XRD. Based on this, a formation mechanism of the interface structure was elucidated. Experimental and analytical results show that two reaction layers have formed during the diffusion bonding of TAD to TC2. One is Al rich α(Ti)layer adjacent to TC2,and the other is (Ti 3Al+TiAl)layer adjacent to TAD,thus the interface structure of the TAD/TC2 joints is TAD/(Ti 3Al+TiAl)/α(Ti)/TC2.This interface structure forms according to a three stage mechanism,namely(a)the occurrence of a single phase α(Ti)layer;(b)the occurrence of a duplex phase(Ti 3Al+TiAl)layer;and(c)the growth of the α(Ti)and (Ti 3Al+TiAl)layers.
文摘An overview of a severe kind of environmentally-assisted cracking-stress corrosion cracking (SCC) of pressure vessel steel (PVS),such as stainless steel 304, alloy 600,690 and other nickel-based alloys in subcritical (～300 ℃) aqueous environment was given. The mechanisms of SCC of metals under this inclement surrounding were briefly generalized. Herein,some pragmatic solutions to mitigate the SCC susceptibility and retard its propagation were presented. The titanium and cerium-based inhibitors addition countermeasure was highlighted.
文摘For developing TiO based imitated gold materials, the wettabilities of Fe and Fe Cr Ni Ti on TiO were studied. The results indicated that the wettabilities of Fe and Fe Cr on TiO were poor, and their wetting angles were about 90° at melting point. The wetting angles reduced with the increase of wetting temperature, but the influence of temperature was small. Fe and Fe Cr containing Cr 50% or less could react with TiO on the interface to form Fe 2Ti and Ti 2O 3, but this did not improve the wettability effectively. When Ni Ti was added into Fe Cr alloy, Ni 3Ti was formed on the interface, which can reduce the interface energy, improve the wettability, and prevent the formation of Fe 2Ti and Ti 2O 3. The wetting angles could go down to about 40° when 3% Ni Ti was added to Fe Cr alloy.
