• Title/Summary/Keyword: silicate

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Effect of the Moisture Content in Sodium Silicate Binder on Bending Strength of Sand Core (규산나트륨 바인더 수분함량이 중자 굽힘강도에 미치는 영향)

  • Panseong Kim;Min A Ber;Man Sig Lee;Jae Ho Baek
    • Journal of Korea Foundry Society
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    • v.44 no.3
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    • pp.70-76
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    • 2024
  • Sodium silicate binder is eco-friendly inorganic binder to substitute organic binder in foundry industry, but it has low stability at moisture. In this study, the bending strength of sand cores with sodium silicate binder at various curing condition was measured for confirm the effect of moisture content in cured sodium silicate binder on the strength and stability. The sodium silicate binder generates stable binder bridge with silicate structure of Q3 and Q2 at 130℃. The maximum bending strength of sand cores was not affected by curing conditions, because the silicate structure of binder bridges was similar. However, the lower moisture content of cured sodium silicate binder, stability of strength was enhanced. Therefore, it was confirmed that the moisture content of cured sodium silicate binder is important factor at stability of sodium silicate binder.

Partial Discharge Resistance According to Frequency Acceleration Deterioration of Epoxy/Layered Silicate Nanocomposites (에폭시/층상실리케이트 나노콤포지트의 주파수 가속열화에 따른 부분방전 저항성)

  • Park, Jae-Jun
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.62 no.12
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    • pp.1694-1699
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    • 2013
  • Frequency accelerated partial discharge resistance (PDR) aging of epoxy/layered silicate nanocomposite with 1.5wt % additions of layered silicate was investigated in comparison with that of epoxy without layered silicate in terms of PD(partial discharge) erosion depth. It was found that the change in the erosion depth is far smaller in specimens with layered silicate than those without layered silicate nano particles. Frequency acceleration can be done from 60Hz to 1000Hz. But the depth of erosion is less proportional to frequency. Acceleration factor is almost 2 times between 500Hz and 1000Hz, but it is much less than about 8.3 times between 60Hz and 500Hz. This superior PD resistance is caused by the presence of nanofillers, anano-effect due to closely packed nanofillers, and strong chemical bonds at layered silicate nanofillers /resin interfaces.

Dielectric Properties of Epoxy/Organically Modified Layered Silicate Nanocomposites (에폭시/유기적으로 변경된 층상실리케이트가 충진 된 나노콤포지트의 유전특성)

  • Park, Jae-Jun
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.21 no.2
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    • pp.188-193
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    • 2008
  • Epoxy/Organically Modified Layered Silicate Nanocomposites were prepared by dispersing synthetic layered silicate modified with alkyl ammonium ions. In the dispersing process, the organically modified layered silicate were mixed in epoxy resin with shearing, and aggregation of the silicate were removed by centrifugal separation after mixing epoxy resin and silicates. Micrographs taken by transmission electron microscopy(TEM) indicate that the nanocomposites have a mixed morphology including both parallel silicate layers and exfoliated silicate layers area, As the thermal properties, the glass transition temperature of the nanocomposites was shifted to a higher temperature($+6^{\circ}C$)than pure epoxy. Furthermore, dispersion of OMLS will prevented relative permittivity from increasing at a high temperature above the glass transition temperature.

Expansion Characteristics of the Hydrated Sodium Silicate (수화된 규산소다의 팽창 특성)

  • Kong, Yang-Pyo;Cho, Ho-Yeon;Suhr, Dong-Soo
    • Journal of the Korean Ceramic Society
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    • v.45 no.1
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    • pp.54-59
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    • 2008
  • Hydrated sodium silicate with 25 wt% water contents was synthesized by hydrothermal reaction using anhydrous sodium silicate. The hydrated sodium silicate was expanded at $370^{\circ}C$ for 30 min. and then pulverized, classified (- 200 mesh) and press-formed. The samples were heat treated at $400{\sim}900^{\circ}C$ for 30 min. in order to study the expansion characteristics depending on heat treatment temperature. A porous body with closed pore was formed above $600^{\circ}C$. The volume expansion ratio and the pore size were increased and the specific gravity was decreased with increasing heat treatment temperature. However, the volume expansion ratio was decreased and the specific gravity was increased above $850^{\circ}C$ due to the softening of the sodium silicate.

The Study of Hafnium Silicate by NO Gas Annealing Treatment (NO gas 후속 열처리를 통한 Hf-silicate에 대한 연구)

  • Cho, Young-Dae;Seo, Dong-Chan;Ko, Dae-Hong
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2007.11a
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    • pp.117-117
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    • 2007
  • The physical and electrical properties of nitrided Hf-silicate films, incorporated by NO gas annealing, were investigated by XPS, NEXAFS, TEM and C-V measurement. We confirmed the nitrogen incorporation during NO gas annealing treatment effectively enhances the thermal stability of Hf-silicate. The suppression of phase separation was observed in Hf-silicate films with high nitrogen contents. The negative shift of threshold voltage is caused by the incorporation of nitrogen in the hafnium silicate films.

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Farmer's Field Trial of Different Coating and Covering Materials on Rice Growth and Yield in Wet Hill Seeded Rice (볍씨 코팅 및 규산복토에 따른 벼 무논점파재배 농가실증시험연구)

  • Park, Kwang Ho;Kim, Yang Sik;Chang, Jin Tack
    • Journal of Practical Agriculture & Fisheries Research
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    • v.17 no.1
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    • pp.85-92
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    • 2015
  • The experiment was conducted to evaluate rice growth and yield as affected by different coating and covering materials such as a iron, silicate, iron and silicate mixture of rice seeds in farmer's rice growing field. The tiller number was 36.7 at iron-coated seeds, 32.8 at silicate-covered seeds, 30.3 at iron and silicate mixture coated seeds and 30.2 at untreated control in 44days after seeding. The seedling height was 38.2cm of iron and silicate mixture, 37.7cm of untreated control, 36cm of iron-coated and 35.7cm of silicate covered seeds in 43days after seeding. At 75days after seeding rice tiller number was 153 of iron-coated seeds, 152 of silicate-covered seeds, 147 of untreated seeds and 141 of iron and silicate mixture-coated seeds and also there were different plant height growth of 87.4cm in silicate-covered seeds, 85.7cm in iron and silicate mixture, 85.4cm in untreated control and 83.0cm in iron-coated seeds. The panicle length was of 21.0cm in iron and silicate mixture coated seeds, 20.8cm in silicate covered seeds, 20.7cm in untreated control seeds and 20.6cm in iron-coated seeds. The panicle number was 464 at iron-coated seeds, 404 at untreated control seeds, 427 at silicate-covered seeds and 412 at iron and silicate mixture coated seeds. The spikelet number per m2 was of 32,503 in iron-coated seeds, 31,813 in silicate-covered seeds, 29,646 in untreated control, 28,896 in iron and silicate mixture coated seeds. The ripened ratio of rice grain was of 94.5% at iron-coated seeds, 93.9% at iron and silicate mixture coated seeds, 93.6% at silicate covered seeds and 93.2% at untreated control seeds. The rice yield was of 591kg/10a at iron-coated seeds, 580kg/10a at silicate-covered seeds, 571kg/10a at iron and silicate mixture-coated seeds and 539kg/10a at untreated control.

The Effect of Hydration Retarder on Initial Compressive Strength of Sodium Silicate-Cement Grouted Soil (시멘트 수화지연제가 규산나트륨-시멘트 그라우트 초기강도에 미치는 영향에 관한 연구)

  • Chun, Byung-Sik;Yoo, Young-Nam
    • Proceedings of the Korean Geotechical Society Conference
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    • 2005.10a
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    • pp.453-460
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    • 2005
  • Sodium silicate - the usual portland cement which accomplishes a cement pouring reconsideration main stream and sodium silicate(No.3) after reacting sodium silicate(No.3) with the reaction sodium silicate where oxidation natrium which is included does not react with the cement receiving stiffening water it will burn together on underwater and to become the durability lacks pouring it is recognized. From the hazard which improves an advantage it used the additive which relates in congealing and stiffening of the portland cement and sodium tripolyphosphate(STPP) addition hour initial material age(72 hours at once) which does to be revealed the at high-in-tensity is discovered while accomplishing. The effect of additives on the reactions of sodium silicate solution and cement suspesion was investigated by various physical and chemical tests, such as Si-NMR, XRD, SEM uniaxial compression test. The additives were STPP(sodium tripolyphosphate), EDTA, SUGAR. The compressive strength of sodium silicate(No.3) - cement grout with additives was about $1.5{\sim}10$ times higher than that without additive in early age(72 hours).

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Effect of L.D Converter Slag Hardener on the Collapsibility of Sand Molds Using Sodium Silicate Binder (규산소오다계 자경성주형의 붕괴성에 미치는 L.D 전로 슬래그 경화제의 영향)

  • Choi, Jun-Oh;Park, Sung-Taik;Han, Yun-Sung;Choi, Chang-Ock
    • Journal of Korea Foundry Society
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    • v.23 no.5
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    • pp.235-243
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    • 2003
  • The collapsibility of sodium silicate-bonded sands mixed with the L.D converter slag powder to form a hardener were investigated. Five to six percent sodium silicate on the basis of silica sand and 30-40% L.D converter slag powder on the basis of sodium silicate, were mixed and the compressive strength, surface stability index(SSI), bench time, retained strength of the standard sand specimens were measured. The properties were similar to those of general inorganic bonded self-setting molds. The compressive strength and surface stability index were increased and the retained strength and bench time were decreased with increased amount of the L.D converter slag powder. The retained strength of sodium silicate-bonded self-setting molds with the L.D converter slag powder were decreased than $CO_2$ sand molds. The collapsibility of sodium silicate-bonded self-setting molds with the L.D converter slag powder were superior in comparison with $CO_2$ sand molds. The L.D converter slag powder could be used as hardener and collapse agent for the sodium silicate-bonded self-setting molds.

Improvement research for impact strength of nylon66/silicate composites (나일론66/실리케이트 복합체의 충격특성 개선 연구)

  • Lee, Bom Yi;Kim, Youn Cheol
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.15 no.7
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    • pp.4653-4658
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    • 2014
  • A study of the improvement in the impact strength is required to apply Nylon 66/silicate composites as an automobile material. Nylon 66/silicate composites were prepared using a twin screw extruder in case of a silicate treatment by ${\gamma}$-APS (S-silicate) and the addition of an octene ${\alpha}$ olefin grafted by maleic anhydride (PE-g-MAH). The chemical structure of the silane treated silicate was measured by Fourier transform infra-red (FT-IR) spectroscopy. The chemical reaction was confirmed by the decrease in the FT-IR intensity of the OH stretching vibration. The thermal properties, intercalation structure, and Izod impact strength were measured by DSC, TGA, XRD, and Izod impact tester. There was no significant effect on the degradation temperature of the Nylon66/silicate composite, but the crystallization temperature and crystallinity increased slightly in the case of the Nylon66/silicate composites. This suggests that the additives act as heterogeneous nuclei on the Nylon 66 matrix. The Izod impact test indicated that S-silicate enhanced the impact performance by up to 24%.

Studies on the Sequestering Agents to Replace Silicate in Peroxide Bleaching System (과산화수소 보존표백시 Silicate 대체 약품에 관한 연구)

  • Kim, Sung-Kwon;Choung, Sung Wook;Michalowski, R.J.
    • Applied Chemistry for Engineering
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    • v.9 no.5
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    • pp.754-757
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    • 1998
  • This study was carried out to investigate the effect of replacing silicate by Versenate PS peroxide stabilizer in a peroxide bleaching system of deinked pulp process. To evaluate the possibility of replacement, optimization of pretreatment and caustic in bleaching for stock treated with silicate and Versenate PS were performed. After these performance, residual peroxide content and brightness were measured. Results obtained form this study were summarized as follows : 1. Caustic concentration in bleaching system treated with silicate was optimized at 2.5~3.0%. 2. Caustic concentration in bleaching system treated with Versenate PS was optimized at 1.0~1.5%. 3. Versenate PS alone did not provide satisfying bleaching effect. 4. Bleaching system treated with Versenate PS had potential to reduce silicate. 5. DTPA pretreatment provided higher bleaching efficiency.

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