共查询到20条相似文献,搜索用时 31 毫秒
1.
Guang Yang Xianghua Zhang Jing Ren Yang Yunxia Guorong Chen Hongli Ma J. L. Adam 《Journal of the American Ceramic Society》2007,90(5):1500-1503
The glass-forming region in a GeSe2 –As2 Se3 –PbSe system was determined, and the dependence of properties on the composition as a formula of 20 GeSe2 –(80− x )As2 Se3 − x PbSe ( x =0–30) was investigated. Measurements include density, differential scanning calorimetry, X-ray diffraction, Vis-NIR, and IR transmission spectra. A fairly large glass-forming region was obtained where the higher lead content could be introduced into the system in the As2 Se3 -rich region than in the GeSe2 -rich region. With the introduction of PbSe, the density of glass increased and the calculated molar volume decreased while the crystallization tendency increased, which was indicated by the decreasing Δ T ( T x − T g ). The activation energy of crystallization and the Avrami exponents were also obtained using the modified Ozawa equation. Under proper annealing conditions, suitable IR transmittance glass–ceramics were obtained. 相似文献
2.
Zhao Donghui Xia Fang Chen Guorong Zhang Xianghua Ma Hongli J. L. Adam 《Journal of the American Ceramic Society》2005,88(11):3143-3146
The glass-forming region in a GeSe2 –As2 Se3 –CdSe system and the dependence of properties on glass compositions as a formula of 70GeSe2 –(30− x )As2 Se3 – x CdSe ( x =0–25) were investigated. Measurements included density, micro-hardness, differential scanning calorimetry (DSC), X-ray diffraction, and IR transmission spectra. A large glass-forming region was shown while addition of Cd increases the crystallization trend of the system. Besides, the Cd content accommodated by the system to form glass is found to be lower in the As2 Se3 -rich region than in the GeSe2 -rich region. With the introduction of CdSe, density, micro-hardness, and T g of glasses increase whereas an exothermal peak in the DSC curve appears and thermal stability (Δ T ) decreases. The activation energy of crystallization and the Avrami exponent were also obtained using the modified Ozawa equation. 相似文献
3.
Gao Tang Zhiyong Yang Lan Luo Wei Chen 《Journal of the American Ceramic Society》2008,91(5):1686-1689
The glass-forming region of the GeSe2 –Ga2 Se3 –PbI2 system was determined and homogeneous glasses were prepared. The maximum dissolvable PbI2 can be up to 50 mol%. The structures of glasses were characterized by Raman spectroscopy. The thermal, optical, and some basic physical properties of the glasses were investigated. The results show that GeSe2 –Ga2 Se3 –PbI2 glasses have a wide region of transmission window (0.7–16 μm) and high refractive index (∼2.5) with the addition of PbI2 . The glasses have good glass-forming ability and high glass transition temperatures. Consequently, these novel glasses may be promising candidate materials for infrared optics and nonlinear optical field. 相似文献
4.
Infrared transmitting glass–ceramics based on the selected glass of 65GeSe2 –25Ga2 Se3 –10CsI were obtained by a two-stage heat-treatment method. Results of X-ray diffraction and scanning electronic microscopy indicated that droplet-like nanoparticles containing cubic Ga2−δ Geδ Se3 crystals are homogeneously generated in the glass–ceramics and that the whole glass–ceramic process is composed of phase separation, nucleation, and crystal growth. Evolutions of the optical and mechanical properties of glass–ceramics versus annealing time at the first-stage heat treatment were also investigated. Compared with the parent glass, the fabricated glass–ceramics show considerably enhanced fracture toughness, practicable infrared transparence, and microhardness, which confer them with considerable competitive advantages over currently used infrared materials. 相似文献
5.
GeSe2 –Ga2 Se3 –CsI chalcohalide glasses are synthesized, and their optical properties and thermo-mechanical properties are studied. A typical characteristic of the glasses is their excellent transparency in the red-light region in addition to the 8–14 μm atmospheric window, which is of vital importance to the quality control of infrared systems. The short-wavelength absorption edge λs of the glass system has a distinct blue shift with increasing CsI content, and the physicochemical interpretations are suggested and formulated. These glasses present a glass transition temperature ( T g ) around 300°C and good thermal stability. Consequently, they can be promising candidate materials for infrared optics, although their hardness is relatively weak. 相似文献
6.
GeSe2 –Ga2 Se3 –KX (X=I, Br, or Cl) chalcohalide glasses are synthesized, and their optical properties and thermo-mechanical properties are investigated. A structural model is put forward to elucidate the interesting compositional dependences of the short-wavelength absorption edge (λs ) and glass transition temperature ( T g ). These glasses are transparent in the red-light region in addition to the 3–5 and 8–14 μm atmospheric windows. Most of their T g exceed 300°C, and they also present good thermal stability. These properties make them attractive materials for infrared optics. 相似文献
7.
Zhiyong Yang Wei Chen Hongli Ma Xianghua Zhang 《Journal of the American Ceramic Society》2008,91(8):2720-2723
This is an attempt to produce molded 8–14 μm transmitting glass–ceramics by a one-step molding technique. Controlled crystallization is expected to be carried out during application of an appropriate molding process to pure glasses. GeSe2 –Ga2 Se3 –CsI chalcohalide glass was used for the attempt, and well-designed molding parameters were applied to the glass. The results indicate that large quantities of submicrometer crystalline particles are formed and regularly distributed inside the glass matrix during the molding, leading to improved toughness without influencing the 8–14 μm transmittance. This phenomenon implies that it is possible and convenient to produce molded glass–ceramics by a one-step molding technique. 相似文献
8.
Yaping Zhang Yunxia Yang Yuwen Ou Wei Hua Jiahua Zheng Guorong Chen 《Journal of the American Ceramic Society》2009,92(8):1881-1883
Glasses with compositions 50Bi2 O3 – x Sb2 O3 –10B2 O3 –(40– x ) SiO2 ( x =0, 1, 3, 5, 8, 10) have been prepared by conventional melt quench technique. Substitution of Sb2 O3 for SiO2 exerted an obvious effect on properties of glasses, especially, increased glass transition temperature ( T g ) and crystalline temperature ( T c ) greatly. Results of infrared transmission spectra attributed the effect to the formation of new bridging bonds of Sb–O–B and Sb–O–Si in glass network. 相似文献
9.
Zaine Teixeira Oswaldo Luiz Alves Italo Odone Mazali 《Journal of the American Ceramic Society》2007,90(1):256-263
The FTIR, Raman, UV-Vis, 31 P MAS-NMR, DTA, and refractive index measurements have been combined to investigate a series of glasses with the general formula 20Na2 O–5Al2 O3 − x TiO2 –(45− x )Nb2 O5 –30P2 O5 , 15≤ x ≤45. The glass structure, as well as thermal, optical, and chemical durability properties, were then described as functions of the f Nb / f Ti ratio. An increase of the f Nb / f Ti ratio correlates with a decrease in length of the average phosphate chains linked through Nb–O–P and Ti–O–P bonds, with an increase in the glass stability and with increase in the linear refractive indices at 632.8 nm from 1.79 to 1.89. Furthermore, niobium is more effective than titanium in improving chemical durability. 相似文献
10.
Subsolidus phase relationships in the Ga2 O3 –In2 O3 –SnO2 system were studied by X-ray diffraction over the temperature range 1250–1400°C. At 1250°C, several phases are stable in the ternary system, including Ga2 O3 ( ss ), In2 O3 ( ss ), SnO2 , Ga3− x In5+ x Sn2 O16 , and several intergrowth phases that can be expressed as Ga4−4 x In4 x Sn n −4 O2 n −2 where n is an integer. An In2 O3 –SnO2 phase and Ga4 SnO8 form at 1375°C but are not stable at 1250°C. GaInO3 did not form over the temperature range 1000–1400°C. 相似文献
11.
Takashi Wakasugi Rikuo Ota Jiro Fukunaga 《Journal of the American Ceramic Society》1992,75(11):3129-3132
In order to evaluate the crystallization tendency of glasses, the ratio of the crystallization temperature to the liquidus temperature ( T c / T L ) was obtained by DTA measurement for the Na2 O–B2 O3 and Na2 O–B2 O3 –Al2 O3 systems. The critical cooling rate for glass formation ( Q *) was also measured. The measurements were performed in the composition range of (100 − x )Na2 O–( x )B2 O3 , ( x = 25–35 and 60–100 mol%), and (100 − y )0.5Na2 O·0.5B2 O3 −( y )Al2 O3 , ( y = 6–34 mol%). The relationship between T c / T L and Q * was discussed. A linear relationship between T c / T L and log Q * for these systems was found. Furthermore, the relationship between T c / T L and Q * was verified by computer simulation based on the crystallization kinetics of glass or supercooled liquid. 相似文献
12.
Subsolidus phase relationships in the Ga2 O3 –Al2 O3 –TiO2 system at 1400°C were studied using X-ray diffraction. Phases present in the pseudoternary system include TiO2 (rutile), Ga2−2 x Al2 x O3 ( x ≤0.78 β-gallia structure), Al2−2 y Ga2 y O3 ( y ≤0.12 corundum structure), Ga2−2 x Al2 x TiO5 (0≤ x ≤1 pseudobrookite structure), and several β-gallia rutile intergrowths that can be expressed as Ga4−4 x Al4 x Ti n −4 O2 n −2 ( x ≤0.3, 15≤ n ≤33). This study showed no evidence to confirm that aluminum substitution of gallium stabilizes the n =7 β-gallia–rutile intergrowth as has been mentioned in previous work. 相似文献
13.
Tsuyoshi Honma Yasuhiko Benino Takumi Fujiwara Takayuki Komatsu Ryuji Sato 《Journal of the American Ceramic Society》2005,88(4):989-992
The glass formation region, crystalline phases, second harmonic (SH) generation, and Nd:yttrium aluminum garnet (YAG) laser-induced crystallization in the Sm2 O3 –Bi2 O3 –B2 O3 system were clarified. The crystalline phases of Bi4 B2 O9 , Bi3 B5 O12 , BiBO3 , Sm x Bi1− x BO3 , and SmB3 O6 were formed through the usual crystallization in an electric furnace. The crystallized glasses consisting of BiBO3 and Sm x Bi1− x BO3 showed SH generations. The formation of the nonlinear optical BiB3 O6 phase was not confirmed. The formation (writing) region of crystal lines consisting of Sm x Bi1− x BO3 by YAG laser irradiation was determined, in which Sm2 O3 contents were∼10 mol%. The present study demonstrates that Sm2 O3 –Bi2 O3 –B2 O3 glasses are promising materials for optical functional applications. 相似文献
14.
Ren Jing Yang Guang Zeng Huidan Zhang Xianghua Yang Yunxia Chen Guorong 《Journal of the American Ceramic Society》2006,89(8):2486-2491
In the present work, properties of Dy3+ -doped chalcogenide glasses as a stoichiometric formula of (0.9− x )GeSe2 – x AsSe3/2 –0.1GaSe3/2 ( x =0.1, 0.2, 0.3, 0.4, 0.5, 0.6) were investigated as a comparison with the previously studied Ge–Ga–Se system. Property measurements include differential thermal analysis, density, Vis-NIR and IR transmission spectra, and fluorescent emission spectra. Judd–Ofelt analysis was performed using the calculated oscillator strengths of glasses. All properties of glasses show obvious dependence on compositions. Especially, the improved devitrification resistance and the longer fluorescence life at 1.34 μm emission were observed with the increasing As content. Noticeably, abnormal changes in some properties occurred to the glass whose average coordination number corresponds to the threshold of two-dimensional–three-dimensional topological phase transition. 相似文献
15.
Wei Zheng Xiaofeng Lu Wei Wang Bo Dong Hongnan Zhang Zhaojie Wang Xiuru Xu Ce Wang 《Journal of the American Ceramic Society》2010,93(1):15-17
In this paper, we presented a simple and effective electrospinning technique for the preparation of In2 O3 –SnO2 composite nanofibers. The morphology and chemical structure of the as-prepared samples were analyzed by scanning electron microscopy, transmission electron microscopy, and X-ray diffraction. The results showed that large quantities of In2 O3 –SnO2 composite nanofibers with diameters from 60 to 100 nm were obtained. The In2 O3 –SnO2 composite nanofibers exhibited excellent gas sensing properties to methanol, such as fast response/recovery properties, high sensitivity, and good selectivity. 相似文献
16.
Riham Michelle Morcos Jean Tangeman Sergey Ushakov Alexandra Navrotsky 《Journal of the American Ceramic Society》2008,91(4):1088-1094
A series of La2 O3 –HfO2 –SiO2 glasses, approximately along the join 0.73SiO2 –0.27( x HfO2 –(1− x )La2 O3 ), 0< x <0.3), was prepared using containerless processing techniques (aerodynamic levitation combined with laser heating in oxygen). The enthalpy of formation and enthalpy of vitrification at 25°C were obtained from drop solution calorimetry of these glasses and appropriate crystalline compounds in a molten lead borate (2PbO–B2 O3 ) solvent at 702°C. The enthalpy of formation from crystalline oxides was exothermic and became less exothermic with increasing HfO2 content. Heat contents were measured by transposed temperature drop calorimetry and depended linearly on the HfO2 content. Differential scanning calorimetry showed that both the onset glass transition and the onset crystallization temperature of these glasses increased with increasing HfO2 content. Upon slow cooling in air, the glasses crystallized to a mixture of baddeleyite, cristobalite, lanthanum disilicate, and hafnon. 相似文献
17.
The monolithic glass-forming region of the low phonon and low softening point antimony glasses containing high Sb2 O3 (40–75 mol%) in the novel quaternary K2 O–B2 O3 –Sb2 O3 –ZnO system has been found with the help of X-ray diffraction (XRD) analysis. The structure of a series of glasses with the general composition of (mol%) 15K2 O–15B2 O3 –(70− x )Sb2 O3 – x ZnO (where x =5–25) has been evaluated by infrared reflection spectral (FT-IRRS) analyses. All the glasses are found to possess a low phonon energy of around 600 cm−1 , as revealed by FT-IRRS. Their softening point ( T s ), glass transition temperature ( T g ), and coefficient of thermal expansion (CTE) have been found to vary in the ranges of 351°–379°C, 252°–273°C, and 195–218 × 10−7 K−1 , respectively. These properties are found to be controlled by their fundamental property, like the covalent character of the glasses, which is found to increase with an increase in Sb2 O3 content. In addition, the devitrified glasses have been characterized by XRD and field emission scanning electron microscopy, which manifests the presence of nanozinc antimony oxide crystals with sizes of 21–43 nm. The exhibited properties have revealed that they are a new class of versatile materials. 相似文献
18.
Marcus Hoffmann† Christiane Hofer† Theodor Schneller† Ulrich Böttger† Rainer Waser†‡ 《Journal of the American Ceramic Society》2002,85(7):1867-1869
The aging behavior of the solid-solution series (Pb(Mg1/3 Nb2/3 )O3 )1− x –(PbTiO3 ) x (PMN1− x −PT x ) prepared by chemical-solution deposition without seeding layers was investigated. A strong influence of the rapid thermal annealing step on the film density was determined. The best nucleation and density of the thin films occurred when each deposited layer was separately pyrolyzed and crystallized. The thin-film microstructure was investigated using scanning electron microscopy. Conventional capacitance-voltage and hysteresis measurements were performed. For the first time, investigations on the fatigue performance and the leakage current for alternating-current and direct-current voltage were executed, which are important for the reliability in device applications. 相似文献
19.
Two cubic pyrochlore phases exist in the system ZnO–Bi2 O3 –Sb2 O5 . Neither has the supposed "ideal" stoichiometry, Zn2 Bi3 Sb3 O14 . One, P 1 , is a solid solution phase, Zn2+ x Bi2.96−( x − y ) Sb3.04− y O14.04+δ where 0< x <0.13(1), 0< y <0.017(2) and a =10.4285(9)−10.451(1) Å. The other, P 2 , is a line phase, Zn2 Bi3.08 Sb2.92 O13.92 with a =10.462(2) Å. Subsolidus phase relations at 950°C involving phases P 1 and P 2 in the ZnO–Bi2 O3 –Sb2 O5 phase diagram have been determined. 相似文献
20.
Fang Xia Xianghua Zhang Jing Ren Guorong Chen Hongli Ma J. L. Adam 《Journal of the American Ceramic Society》2006,89(7):2154-2157
In the present work, a large glass-forming region was found in the novel GeS2 –Sb2 S3 –PbS system, in which up to 58 at.% PbS could be incorporated without deteriorating the thermal and physical properties of glasses. Infrared (IR) transmitting glass ceramics with a large amount of small-sized crystals (<100 nm) were then produced by choosing sub-stable compositions and annealing at fairly low temperatures (15°–30°C above T g ) for long durations (up to 100 h). Crystals were identified by X-ray diffraction as Pb2 GeS4 , PbGeS3 , PbS, PbSb2 S4 , etc., depending on base glass compositions. Compared with base glasses, glass ceramics showed much improved thermal shock resistance and fracture toughness, making them good candidate materials for IR optics. 相似文献