• Journal of the Korean Crystal Growth and Crystal Technology
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• v.33 no.6
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• pp.250-254
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• 2023

In this study, Li₂O-BaO-Ga₂O₃-TeO₂-TiO₂-GeO₂ glasses with high transmittance in mid-infrared region and high refractive indices were successfully synthesized. The relationship between glass properties and glass composition was analyzed. In Li₂O-BaO-Ga₂O₃-TeO₂-TiO₂-GeO₂ glass system, as increasing TeO₂ concentration, the refractive index increases and the glass transition temperature decreases. In addition, as increasing BaO concentration, the refractive index increases without decrease of Abbe number. The IR-cut off wavelength shifted to the longer wavelength with increasing TeO₂ and BaO contents due to their large molecular weight. The glass transition temperature significantly decreases when BaO was replaced with Li₂O.

• Journal of the Korean Ceramic Society
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• v.22 no.3
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• pp.29-34
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• 1985

The IR spectra of he heavy metal fluoride glasses showed peaks at $1, 400cm^{-1}$ or $1, 100cm^{-1}$ due to metal oxyfluoride impurities. The intensity of this band and hence the oxide impurity content of the glass could be reduced considerably by the use of reactive atmosphere melting under $CCl_4$ In comparison with the fundamental IR absorption band of heavy metal oxides the oxide impurity bands observed in the heavy metal fluoride glasses are multiphonon bands due to a 2-phonon absorption process. The envelope of the a vs. v curve beyond thue fundamental region shows the exponential fall off of a with increasing v-typical of intrinsic multiphonon absorption. In the multiphonon region the amount of structure is intermediate between that observed for covalent solids and that for ionic solids.

• Korean Journal of Crystallography
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• v.7 no.2
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• pp.133-146
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• 1996

Morphology and infrared absorbing characteristics of Pt-black prepared by electroplating have been investigated with XRD, SEM, and IR spectrophotometer. The Pt later was coated on Au-coated alumina/glass substrates for 1-5 min at pH 1.0-1.5, where a solution of platinum chloride and lead acetate was used as the electrolyte. At the electrical current density of 20-50 mA/㎠, the Pt-black showed a dendritic growth which was characterized by a "tree" shape. Absorptivity of above 90% at IR radiation of 10 m was observed for the Pt absorbing layer with an area density of ≥1.3mg/㎠.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1990.10a
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• pp.105-107
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• 1990

In this study, we prepared plasma polymerized thin films as changing the composition rate of the Ar/CO$_2$, 0 to 100%, for analysing the influence of CO$_2$ gas in plasma polymerization. Power source was the RF frequence (13.56MHz), the monomers were styrene and MMA (Methyl-methacrylate), and substrates were glass and KBr(or NaCl) for IR spectroscopy. The molecular structure of plasma polymerized organic thin films was examined by IR, FT-IR, Gas chromatography and so forth.

• Journal of the Korean Ceramic Society
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• v.43 no.2 s.285
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• pp.136-141
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• 2006

The stabilizing behavior of heavy metals in the silicate glass containing Electric Arc Furnace dust (EAF dust) were studied by the Toxic Characterization Leaching Procedure (TCLP) test, and the change of crystalline phase and glass network structure were investigated as a function of EAF dust content added. The glass containing EAF dust of $30\;wt\%$ an oxygen/network former ratio(R) of $2\~3$ allowing a fairly stable network structure thus showed much lower heavy metal leaching concentration than that for containing EAF dust above $50\;wt\%$ at TCLP test. For the glass containing EAF dust $50\~60\;wt\%$, however, the R was over 3, which weakened the glass network structure and increased the heavy metals leachate. Adding the EAF dust to a glass decreased the degree of Si-O-Si symmetry and increased the number of non-bridging oxygen, which decreased the chemical durability of glasses. When the dust content in a glass was over $70\;wt\%$, the Zn and Fe ions reacted to form the spinel crystal rather than to bind to network structure of glass and leaching concentration of those ions from the specimen decreased, so the spinel phase could be attributed to lowering a heavy metal leaching.

• Korean Journal of Materials Research
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• v.33 no.10
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• pp.414-421
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• 2023

Infrared radiation (IR) refers to the region of the electromagnetic radiation spectrum where wavelengths range from about 700 nm to 1 mm. Any object with a temperature above absolute zero (0 K) radiates in the infrared region, and a material that transmits radiant energy in the range of 0.74 to 1.4 um is referred to as a near-infrared optical material. Germanate-based glass is attracting attention as a glass material for infrared optical lenses because of its simple manufacturing process. With the recent development of the glass molding press (GMP) process, thermal imaging cameras using oxide-based infrared lenses can be easily mass-produced, expanding their uses. To improve the mechanical and optical properties of commercial materials consisting of ternary systems, germanate-based heavy metal oxide glasses were prepared using a melt-cooling method. The fabricated samples were evaluated for thermal, structural, and optical properties using DSC, XRD, and XRF, respectively. To derive a composition with high glass stability for lens applications, ZnO and Sb₂O₃ were substituted at 0, 1, 2, 3, and 4 mol%. The glass with 1 mol% added Sb₂O₃ was confirmed to have the optimal conditions, with an optical transmittance of 80 % or more, a glass transition temperature of 660 ℃, a refractive index of 1.810, and a Vickers hardness of 558. The possibility of its application as an alternative infrared lens material to existing commercial materials capable of GMP processing was confirmed.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.4
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• pp.204-209
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• 2017

Thermal and structural stability in the glass transition region of chalcogenide glasses has been investigated in terms of thermodynamics for application to various optoelectronic devices. In this study, the compositions of $Ge_xSb_{20}Se_{80-x}$ (x = 10, 15, 20, 25, and 30) were selected to investigate the glass stability according to germanium ratios. The chalcogenide bulks were fabricated by using a traditional melt-quenching method. Thin films were deposited by a thermal evaporation system, maintaining the deposition ratio of $3{\sim}5{\AA}$ in order to have uniformity. The thermal and structural properties were measured by a differential scanning calorimeter (DSC) and X-ray diffraction (XRD). The DSC analysis provided thermal parameters and theoretical glass region stabilities. The XRD analysis supported the theoretical stabilities because of where the crystallization peak data occurred.

• Journal of the Korean Ceramic Society
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• v.25 no.5
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• pp.479-487
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• 1988

In this study we studied the function of Glycerol as a DCCA(Drying Control Chemical Additives) in the preparation of silica bulk glas through Sol-Gel method. We used TEOS(Tetra Ethyl Ortho Silicate) and maintained the mixing ratio of TEOS : H2O : EtOH : HCI as 1 : 4 : 4 : 0.0007(mol) and varied glycerol input quantity from 0.1vol% considering the ethnaol input quantity as 100vol%. We investigated the changes from Sol-Gel Synthetic solutions to the glass using DT-TG, FT-IR and other instruments. The results obtained from this experiment showed that the dried gels made from the synthetic solutions containing 0.1-1.0vol% of glycerol were easily heat-treated up to 85$0^{\circ}C$ so that transparant bulk silica glass was prepared.

• Journal of the Korean Ceramic Society
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• v.27 no.3
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• pp.430-436
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• 1990

Glasses of different compositions were synthesized by substituting each component of 56ZrF4-14BaF2-6LaF3-4AlF3-20NaF(ZBLAN) with HfH4, SrF2, GdF3, InF3 and LiF3, each of similar size and chemical property with the component being substituted, respectively. The heating rate used in the DSC runs was 10K/min. All ofthe glasses exhibit glass transition temperatures of 510$\pm$10K, while crystallization temperatures vary between 625 and 720K depending upon different glass compositions. For most glasses crystallization temperatures obtained while cooled are lower than those obtained while heated, but InF3 or SrF2 containing glasses showed opposite trend. HBLAN, ZHBLAN and ZHBLANLi glasses, which were made by substituting HfH4, LiF for ZrF4 and NaF of ZBLAN respectively, showed improvement in the glass stability.

• The Korean Journal of Ceramics
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• v.6 no.1
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• pp.9-14
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• 2000

Glass transition temperature (T/sub g/) is proportional to the quadrupole splitting(Δ) of Fe(III) obtained from the /sup 57/Fe Mossbauer spectra (T/sub g/-Δ rule (1990)). The values of Δ reflect the distortion of Fe(III) atoms, which occupy the sites of network-forming atoms. Heat treatment of potassium vanadate and calcium gallate glasses at around the individual T/sub g/ causes a structural relaxation, accompanying a linear decrease of T/sub g/ and Δ values. These experimental results prove that T/sub g/ decreases with a decrease in the distortion of VO₄, GaO₄, and FeO₄tetrahedra, as the T/sub g/-Δ rule predicted.