• Journal of the Korean Society for Precision Engineering
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• v.21 no.4
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• pp.24-31
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• 2004

The objective of this work is to suggest a mastless pattern fabrication technique using the combination of machining by Nanoindenter(equation omitted) XP and HF wet etching. Sample line patterns were machined on a borosilicate surface by constant load scratch (CLS) of the Nanoindenter(equation omitted) XP with a Berkovich diamond tip, and they were etched in HF solution to investigate chemical characteristics of the machined borosilicate surface. All morphological data of scratch traces were scanned using atomic force microscope (AFM).

• Journal of the Korean Chemical Society
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• v.34 no.4
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• pp.360-369
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• 1990

Borosilicate, HZSM-5 zeolite and iron-substituted borosilicate and HZSM-5 zeolite were prepared and their catalytic properties in methanol conversion were studied. The effects of strength and amount of acid site determined from TPD spectra of ammonia on the product distribution was examined. Selectivity to propylene was high over borosilicate with small amount of strong acid site, but selectivity to aromatic compound was high over HZSM-5 zeolite with large amount of the strong acid site. The participation of weak acid site on the conversion did not confirmed, and the product distribution could be explained in terms of the amount of the strong acid site. Although the amount of the weak acid site was increased by substitution of iron, there was no meaningful change in the product distribution.

• Journal of the Korean Chemical Society
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• v.33 no.4
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• pp.379-387
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• 1989

The synthesis of borosilicate consisted of boron and silicon was stadied. The composition, acidity and adsorption characteristics of synthesized borosilicate were examined. The synthesis rate increased with temperature and concentration of $Na_2O$, but the enhansing effects were different according to the reaction conditons. The synthesis process could be simulated by solution transfer mechanism assuming that crystals grow on the surface of crystal or nuclei with dissolved reactant. Adsorption characteristics of synthesized borosilicate was discussed with temperature programmed desorption patterns of ammonia and propylene and adsorption isotherms of propylene and propane.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.10a
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• pp.182-185
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• 2005

Indentation pattern and line pattern were machined on borosilicate(Pyrex 7740 glass) surface using the combination of mechanical machining by $Nanoi-indenter\circledR$ XP and HF wet etching, and a etch-mask effect of the affected layer of the nano-scratched and indented Pyrex 7740 glass surface was investigated. In this study, effects of indentation and scratch process with etching time on the morphologies of the indented and scratched surfaces after isotropic etching were investigated from an angle of deformation energies.

• Journal of the Korea Institute of Military Science and Technology
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• v.16 no.4
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• pp.507-513
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• 2013

Transparent bulletproof windows play an important role in the munitions industry. The thickness of bulletproof windows including soda-lime silicate(SLS) glass, polyvinyl butyral, poly urethane, main defense(200MD), and safety film was reduced from 40mm to 29mm by adjustment of SLS glass laminated array. Borosilicate glasses generally have lower surface density and more excellent mechanical properties than SLS glass. Borosilicate glass was strengthened by ion exchange in the $KNO_3$ powder. The maximum mechanical properties were observed at $550^{\circ}C$ for 10min. The Vickers hardness, fracture toughness and 3-point bending strength of ion exchanged samples were about $775kg/mm^2$, $1.91MPa{\cdot}m^{1/2}$ and 764MPa each, which are about 27%, 149% and 249% higher than parent borosilicate glass, respectively. The penetration depth of K+ ion at $550^{\circ}C$ for 10min was $59.8{\mu}m$. As a result, the transparent bulletproof windows were predicted to be more lightweight by ion exchange of borosilicate glass. If the SLS glass for bulletproof windows is replaced by ion exchanged borosilicate glass, the bulletproof windows can be expected to be lightweight and thinner.

• Journal of the Korean Chemical Society
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• v.51 no.2
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• pp.178-185
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• 2007

Intermediate pentasil borosilicate zeolite-like materials have been crystallized by a novel method named steam-assisted conversion, which involves vapor-phase transport of water. Indeed, amorphous powders obtained by drying Na2O.SiO2.B2O3.TBA2O gels of various compositions using different boron sources are transformed into crystalline borosilicate zeolite belonging to pentasil family structure by contact with vapors of water under hydrothermal conditions. Using a variant of this method, a new material which has an intermediate structure of MFI/MEL in the ratio 90:10 was crystallized. The results show that steam and sufficiently high pH in the reacting hydrous solid are necessary for the crystallization to proceed. Characterization of the products shows some specific structural aspects which may have its unique catalytic properties. X-ray diffraction patterns of these microporous crystalline borosilicates are subjected to investigation, then, it is shown that the product structure has good crystallinity and is interpreted in terms of regular stacking of pentasil layers correlated by inversion centers (MFI structure) but interrupted by faults consisting of mirror-related layers (MEL structure). The products are also characterized by nitrogen adsorption at 77 K that shows higher microporous volume (0.160 cc/g) than that of pure MFI phase (0.119 cc/g). The obtained materials revealed high surface area (~600 m2/g). The infrared spectrum reveals the presence of an absorption band at 900.75 cm-1 indicating the incorporation of boron in tetrahedral sites in the silicate matrix of the crystalline phase.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07b
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• pp.714-717
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• 2004

알루미노 보로실리케이트계 유리 기본조성 중 알칼리 토류 산화물의 종류 및 함량 변화에 따른 저유전율/저 LTCC 배선 기판의 저온 소성 거동 및 유전 특성을 조사하였다 알칼리 토류 산화물의 종류 및 함량 변화를 통해서 LTCC의 적정 소성온도인 $875^{\circ}C$ 부근을 포함하는 넓은 대역으로 소성수축이 시작되는 온도를 제어할 수 있었으며 유리 프리트와 알루미나 필러의 배합 비율의 변화에 따른 소성거동 및 유전특성의 변화 거동을 조사하였다. 알칼리 토류 산화물 중 유리 조성내의 CaO의 함량이 증가할수록 유리전이점 및 연화점을 증가하는 경향을 보였으며, 알루미나 필러의 첨가량이 증가할수록 소성수축이 시작되는 온도영역은 상향되고 유전율 및 품질계수는 증가하였다. 알칼리 토류 산화물의 조성과 필러인 알루미나의 함량을 제어함으로서 $875^{\circ}C$에서 18% 이상의 선수축율과 유전율 $5.1\sim5.5$ 및 유전손실 0.1% 이하의 우수한 특성을 갖는 저온소결용 LTCC 배선 기판을 얻을 수 있었다.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.4 no.1
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• pp.42-45
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• 1994

Deposition of silicon on pretreated sapphire and glass substrates has been investigated by the solution growth method at low temperatures. An average 14 $\mu\textrm{m}$ thickness of silicon was grown over a large area on sapphire substrate originally coated with a much thinner silicon layer [0.5 $\mu\textrm{m}$ (100) Si/(1102) sapphire)] at low temperatures from $380~460^{\cire}C$. Successful results were obtained from surface treated glass substrates in the temperatures range from $420~520^{\circ}C$.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.7 s.172
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• pp.71-78
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• 2005

The purpose of this study is to suggest a hyperfine maskless writing technique by using the nanoindentation and HF wet etching technique. Indents were made on the surface of Pyrex7740 glass by the hyperfine indentation process with a Berkovich diamond indenter, and they were etched in $50\;wr\%$ HF solution. After etching process, convex structure was obtained due to the deformation-induced hillock phenomena. In this study, effects of indentation process parameters (etching time, normal load, loading .ate, hold-time at the maximum load) on the morphologies of the indented surfaces after isotopic etching were investigated from an angle of deformation energies. Finally, sample characters were written to show the possibility of the application.

• Transactions of Materials Processing
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• v.12 no.7
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• pp.623-630
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• 2003

Nanomachining process, static nanoplowing, is one of the most promising lithographic technologies in terms of the low cost of operation and variety of workable materials. In nanomachining process, chemical effects are more dominant factor compared with those by physical deformation or fracture. For example, during the nanoscratch on a silicon surface in the atmosphere, micro protuberances are formed due to the mechanochemical reaction between diamond tip and the surfaces. On the contrary, in case of chemically stable materials, such as ceramic or glass, surface protuberances are not formed. The purpose of this study is to understand effects of the mechanochemical reaction between tip and surfaces on deformation behaviors of hard-brittle materials. Nanometerscale elasoplastic deformation behavior of single crystal silicon (100) was characterized with micro protuberance phenomena, and compared with that of borosilicate (Pyrex glass 7740). In addition, effects of the silicon protuberances on nanoscratch test results were discussed.