SiO 2-GeO 2 sols and gel glass coatings with different contents of germanium dioxide were fabricated.Stable and transparent sols could only be obtained when the content of GeO 2 was under 35%.It is shown by SEM tha...SiO 2-GeO 2 sols and gel glass coatings with different contents of germanium dioxide were fabricated.Stable and transparent sols could only be obtained when the content of GeO 2 was under 35%.It is shown by SEM that only one continuous phase is observed in the coating of 65SiO 2·35GeO 2 and plenty of Ge,O and Si were all found in it.However,the separated phase is found in the coating of 60SiO 2·40GeO 2 and a large number of Ge and O.It is proved by the Raman scattering investigation that the separated phase in the coating of 60SiO 2·40GeO 2 is germanium dioxide.The congeries of hydrolystates of Cl 3GeCH 2CH 2COOH play the main role in the formation of the separated phase when the proportion of GeO 2 is much higher.Si-O-Ge,Si-O-Si,and Ge-O-Ge bonds form in the coating of 65SiO 2·35GeO 2 and this coating is homogenous.展开更多
The effect of heat treatment on the transformation temperature of Ti?52.2%Ni (mole fraction) alloy was studied using differential scanning calorimetry (DSC). The transformation temperatures of the alloy can be adjuste...The effect of heat treatment on the transformation temperature of Ti?52.2%Ni (mole fraction) alloy was studied using differential scanning calorimetry (DSC). The transformation temperatures of the alloy can be adjusted effectively by heat treatment. Dense and stable SiO2 coatings were deposited on the surface of the pre-oxidized TiNi alloy by sol?gel method. The bonding strength of films and matrix was (65.9±1.5) N. The electrochemical corrosion test shows that the TiNi alloy with SiO2 coating has excellent corrosion resistance in the Hank’s simulated body fluid. The release behaviors of Ni ion of the alloy with and without SiO2 coating implanted in the acoustic vesicle of guinea pig were studied by EDS testing, which was inhibited effectively by the dense and stable SiO2 coating on the alloy.展开更多
To alleviate catalytic coking on the inner surface of radiant tube for ethylene production in petrochemical plants,SiO2/S coatings were deposited on HP40 alloy specimens using dimethyldisulfide （DMDS） and tetraethox...To alleviate catalytic coking on the inner surface of radiant tube for ethylene production in petrochemical plants,SiO2/S coatings were deposited on HP40 alloy specimens using dimethyldisulfide （DMDS） and tetraethoxysilane （TEOS） by atmospheric pressure chemical vapor deposition （APCVD）. A two-dimension mathematical model was made to predict the growth rate of SiO2/S coating and to study the effects of deposition parameters on the deposition rate. The results show that the predicted deposition rate is in good agreement with the experimental one. The deposition rate mainly depends on the concentrations of precursors in the total gas flow, concentrations of intermediates on the deposition surface, total gas flow rate and deposition temperature. The weight of SiO2/S coating linearly increases with the deposition time. When the gas flow rate is below 0.3 m/s, the rate-limiting step of SiO2/S coating deposition is the diffusions of intermediates.However, the surface reactions of intermediates will be the rate-limiting step after the gas flow rate is above 0.3 m/s. When the deposition temperature is below 780℃, the rate-limiting step of SiO2/S coating deposition mainly depends on the surface reactions of intermediates. When the deposition temperature is above 780℃,the rate-limiting step depends on the diffusions of intermediates. The deposition rate increases with increasing the concentrations of the intermediates. However, when the partial pressures of the intermediates reach 8 Pa,the deposition rate keeps constant.展开更多
The dynamic wetting of water spreading on TiO 2 and TiO 2 SiO 2 films prepared by sol gel method and subsequently treated by air plasma and UV irradiation was investigated. Water completely spread on TiO 2 surface wit...The dynamic wetting of water spreading on TiO 2 and TiO 2 SiO 2 films prepared by sol gel method and subsequently treated by air plasma and UV irradiation was investigated. Water completely spread on TiO 2 surface within 3 s and its dynamic contact angles can be expressed by a power law θ d= k(t+a) -n with the n value 0.98. Less than 50%(molar fraction) SiO 2 addition can accelerate the dynamic water spreading rate on the TiO 2 SiO 2 films and the optimum molar fraction of SiO 2 amount corresponding to as annealed, air plasma, and UV irradiation treatment process is 15%, 10% and 20%, respectively.展开更多
A series of SO 2- 4/TiO 2 SiO 2 catalysts with different mass fractions of SiO 2 were prepared by sol gel method. The effect of adding SiO 2 on the crystal structure, specific surface area, oxygen adsorption, and acid...A series of SO 2- 4/TiO 2 SiO 2 catalysts with different mass fractions of SiO 2 were prepared by sol gel method. The effect of adding SiO 2 on the crystal structure, specific surface area, oxygen adsorption, and acidity of SO 2- 4/TiO 2 catalyst and its photocatalytic property for degradation of bromomethane was studied. The results showed that the specific surface area and amount of oxygen adsorption of catalyst were increased by addition of SiO 2, leading to the obvious increase on photocatalytic activity of SO 2- 4/TiO 2 SiO 2 catalysts and mineralization ratio of bromomethane. Comparing with SO 2- 4/TiO 2, the acidic strength and anti moisture ability of SO 2- 4/TiO 2 SiO 2 catalyst were decreased.展开更多
文摘SiO 2-GeO 2 sols and gel glass coatings with different contents of germanium dioxide were fabricated.Stable and transparent sols could only be obtained when the content of GeO 2 was under 35%.It is shown by SEM that only one continuous phase is observed in the coating of 65SiO 2·35GeO 2 and plenty of Ge,O and Si were all found in it.However,the separated phase is found in the coating of 60SiO 2·40GeO 2 and a large number of Ge and O.It is proved by the Raman scattering investigation that the separated phase in the coating of 60SiO 2·40GeO 2 is germanium dioxide.The congeries of hydrolystates of Cl 3GeCH 2CH 2COOH play the main role in the formation of the separated phase when the proportion of GeO 2 is much higher.Si-O-Ge,Si-O-Si,and Ge-O-Ge bonds form in the coating of 65SiO 2·35GeO 2 and this coating is homogenous.
基金Project(81170609)supported by the National Natural Science Foundation of ChinaProject(11JJ6087)supported by the Nature Science Foundation of Hunan Province,ChinaProject supported by the Open Project of State Key Laboratory of Powder Metallurgy,Central South University,China
文摘The effect of heat treatment on the transformation temperature of Ti?52.2%Ni (mole fraction) alloy was studied using differential scanning calorimetry (DSC). The transformation temperatures of the alloy can be adjusted effectively by heat treatment. Dense and stable SiO2 coatings were deposited on the surface of the pre-oxidized TiNi alloy by sol?gel method. The bonding strength of films and matrix was (65.9±1.5) N. The electrochemical corrosion test shows that the TiNi alloy with SiO2 coating has excellent corrosion resistance in the Hank’s simulated body fluid. The release behaviors of Ni ion of the alloy with and without SiO2 coating implanted in the acoustic vesicle of guinea pig were studied by EDS testing, which was inhibited effectively by the dense and stable SiO2 coating on the alloy.
文摘To alleviate catalytic coking on the inner surface of radiant tube for ethylene production in petrochemical plants,SiO2/S coatings were deposited on HP40 alloy specimens using dimethyldisulfide （DMDS） and tetraethoxysilane （TEOS） by atmospheric pressure chemical vapor deposition （APCVD）. A two-dimension mathematical model was made to predict the growth rate of SiO2/S coating and to study the effects of deposition parameters on the deposition rate. The results show that the predicted deposition rate is in good agreement with the experimental one. The deposition rate mainly depends on the concentrations of precursors in the total gas flow, concentrations of intermediates on the deposition surface, total gas flow rate and deposition temperature. The weight of SiO2/S coating linearly increases with the deposition time. When the gas flow rate is below 0.3 m/s, the rate-limiting step of SiO2/S coating deposition is the diffusions of intermediates.However, the surface reactions of intermediates will be the rate-limiting step after the gas flow rate is above 0.3 m/s. When the deposition temperature is below 780℃, the rate-limiting step of SiO2/S coating deposition mainly depends on the surface reactions of intermediates. When the deposition temperature is above 780℃,the rate-limiting step depends on the diffusions of intermediates. The deposition rate increases with increasing the concentrations of the intermediates. However, when the partial pressures of the intermediates reach 8 Pa,the deposition rate keeps constant.
文摘The dynamic wetting of water spreading on TiO 2 and TiO 2 SiO 2 films prepared by sol gel method and subsequently treated by air plasma and UV irradiation was investigated. Water completely spread on TiO 2 surface within 3 s and its dynamic contact angles can be expressed by a power law θ d= k(t+a) -n with the n value 0.98. Less than 50%(molar fraction) SiO 2 addition can accelerate the dynamic water spreading rate on the TiO 2 SiO 2 films and the optimum molar fraction of SiO 2 amount corresponding to as annealed, air plasma, and UV irradiation treatment process is 15%, 10% and 20%, respectively.
文摘A series of SO 2- 4/TiO 2 SiO 2 catalysts with different mass fractions of SiO 2 were prepared by sol gel method. The effect of adding SiO 2 on the crystal structure, specific surface area, oxygen adsorption, and acidity of SO 2- 4/TiO 2 catalyst and its photocatalytic property for degradation of bromomethane was studied. The results showed that the specific surface area and amount of oxygen adsorption of catalyst were increased by addition of SiO 2, leading to the obvious increase on photocatalytic activity of SO 2- 4/TiO 2 SiO 2 catalysts and mineralization ratio of bromomethane. Comparing with SO 2- 4/TiO 2, the acidic strength and anti moisture ability of SO 2- 4/TiO 2 SiO 2 catalyst were decreased.
