Sialon multiphase composites containting titanium-carbon or titanium-nitrogen have been synthesized from clay nd additive titania through different sintering processes,The experimental results indicated that there was...Sialon multiphase composites containting titanium-carbon or titanium-nitrogen have been synthesized from clay nd additive titania through different sintering processes,The experimental results indicated that there was a great change of crystal phase in the similar-composition specimens singtering in air ,nitrogen and bedding protecive poder respectively,determined by XRD analysis,The subsequent evidences were also supplied by SEM.The improvement in mehanical properties of multiphase refracto-ries was observed as the amount of titania changing from 0 to 16%,The main causes maybe come from the excellent properties of high hardness and in-situ strengthening effects of the in-situ formed secondary phase,TiC or TiN.展开更多
CdS microcrystallite doped SiO 2 glass films on titanium metal substrates were prepared by sol gel process. The effects of solution composition and viscosity, heat treatment parameters and substrate pretreatment m...CdS microcrystallite doped SiO 2 glass films on titanium metal substrates were prepared by sol gel process. The effects of solution composition and viscosity, heat treatment parameters and substrate pretreatment method on the film qualities were studied. The transformation process of gel to CdS doped SiO 2 glass film, the structure of these films, the substrate/film interface bonding state and crystalline phase were analyzed by DTA, IRRS, SEM, EDS and XRD. The IRRS results show that Si O Ti linkages are formed between titanium substrate and thin film during heat treatment process. The preferential heat treatment of titanium surface in oxidizing atmosphere will be beneficial to increase the interface bonding strength. The thin films bonded with the substrates chemically and contained very fine CdS crystals with 20～40 nm in size.展开更多
Commercially available niobium (V) oxide [Nb_2O_5], with barium acetate[Ba(CH_3COO)_2] and magnesium acetate [Mg(CH_3COO)_2·4H_2O] was used as the starting material inthe sol-gel process for preparing Ba(Mg_(1/3)...Commercially available niobium (V) oxide [Nb_2O_5], with barium acetate[Ba(CH_3COO)_2] and magnesium acetate [Mg(CH_3COO)_2·4H_2O] was used as the starting material inthe sol-gel process for preparing Ba(Mg_(1/3)Nb_(2/3))O_3 (BMN) nanopowders. At first, Nb_2O_5reacted with melting sodium hydroxide and transformed into dispersible oxide. The resulting glassysubstance after cooling was dispersed and washed several times in distilled water to remove the Na^+ions. The as-prepared colloidal Nb_2O_5·nH_2O was subsequently mixed with acetic solution ofbarium acetate and magnesium acetate according to the required molar proportions and followed bygelation. The ultrafine BMN powders were finally obtained after heat-treating the gel at 820℃ for 1h, and the as-sintered nanoceramics revealed a high relative density of 98.2%, and a high microwaveQ-factor, of 10397 at 1,45GHz.展开更多
文摘Sialon multiphase composites containting titanium-carbon or titanium-nitrogen have been synthesized from clay nd additive titania through different sintering processes,The experimental results indicated that there was a great change of crystal phase in the similar-composition specimens singtering in air ,nitrogen and bedding protecive poder respectively,determined by XRD analysis,The subsequent evidences were also supplied by SEM.The improvement in mehanical properties of multiphase refracto-ries was observed as the amount of titania changing from 0 to 16%,The main causes maybe come from the excellent properties of high hardness and in-situ strengthening effects of the in-situ formed secondary phase,TiC or TiN.
文摘CdS microcrystallite doped SiO 2 glass films on titanium metal substrates were prepared by sol gel process. The effects of solution composition and viscosity, heat treatment parameters and substrate pretreatment method on the film qualities were studied. The transformation process of gel to CdS doped SiO 2 glass film, the structure of these films, the substrate/film interface bonding state and crystalline phase were analyzed by DTA, IRRS, SEM, EDS and XRD. The IRRS results show that Si O Ti linkages are formed between titanium substrate and thin film during heat treatment process. The preferential heat treatment of titanium surface in oxidizing atmosphere will be beneficial to increase the interface bonding strength. The thin films bonded with the substrates chemically and contained very fine CdS crystals with 20～40 nm in size.
文摘Commercially available niobium (V) oxide [Nb_2O_5], with barium acetate[Ba(CH_3COO)_2] and magnesium acetate [Mg(CH_3COO)_2·4H_2O] was used as the starting material inthe sol-gel process for preparing Ba(Mg_(1/3)Nb_(2/3))O_3 (BMN) nanopowders. At first, Nb_2O_5reacted with melting sodium hydroxide and transformed into dispersible oxide. The resulting glassysubstance after cooling was dispersed and washed several times in distilled water to remove the Na^+ions. The as-prepared colloidal Nb_2O_5·nH_2O was subsequently mixed with acetic solution ofbarium acetate and magnesium acetate according to the required molar proportions and followed bygelation. The ultrafine BMN powders were finally obtained after heat-treating the gel at 820℃ for 1h, and the as-sintered nanoceramics revealed a high relative density of 98.2%, and a high microwaveQ-factor, of 10397 at 1,45GHz.
