• Korean Journal of Materials Research
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• v.5 no.2
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• pp.232-238
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• 1995

The thermal stress distribution of WC and Ni binder phases In WC-26st.%Ni and WC-6wt.%Ni composites has been investigated over the temperature range 100-900 K using a time-of-flight neutron diffractometer. To determine the stress distribution, the breadths of WC and Ni peaks in the reference powder and the composites were analyzed. The peak breadths were corrected for particle size effect using a procedure based on the integral peak breadth method of particle size-strain analysis. The result shows a broad range of strain, and thus stress, is present in the WC and Ni binder phases of the composites. The strain distribution of both phases broadens as the temperature decreases, and some fraction of total strain distribution of the WC phase remains tensile regardless of the temperature. The strain distribution of the WC phase broadens as the binder content increases, and that of Ni binder phase broadens as the binder content decreases, which means the strain distribution broadens as the absolute value of residual stress increase.

• Journal of Powder Materials
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• v.7 no.1
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• pp.27-34
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• 2000

The fabrication process and mechanical properties of SiC particle prefrrms with high volume fraction ranged 50∼71% were investigated to make metal matrix composites for possible applications as heat sinks in electronic packares. The SiC particle preforms with 50∼71vol% of reinforcement were fabricated by a new modified process named ball milling and pressing method. The SiC particle performs were fabricated by ball milling of SiC particles with single sized of 48${\mu}$m in diameter or two different size of 8${\mu}$m and 48${\mu}$min diameter, with collodal SiO2 as inorgnic binder in distilled water, and the mixed slurries were cold pressed for consolidation into final prefom. The compressive strengths og calcined SiC particle prefoms increased from 20MPa to 155MPa with increasing the content of inorganis binder, temperature and time for calcination. The increase of compressive strength of SiC particle bridge the interfaces of two neighboring SiC particles.

• Journal of the Korean Society of Radiology
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• v.3 no.1
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• pp.11-15
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• 2009

In this study, the basic research verifying possibility of applications as radiology image sensor in Digital Radiography was performed, the radiology image sensor was fabricated using a multi-layer technique to decrease dark current. High efficiency materials in substitution for Amorphous Selenium(a-Se) have been studied as a direct method of imaging detector in Digital Radiography to decrease dark current by using PN junction or Hetero junction already used as solar cell, semiconductor. Particle-In -Binder method is used to fabricate radiology image sensor because it has a lot of advantages such as fabrication convenient, high yield, suitability for large area sensor. But high leakage current is one of main problem in Particle-In -Binder method. To make up for the weak points, multi-layer technique is used, and it is considered that high efficient digital radiation sensor can be fabricated with easy and convenient process. In this study, electrical properties such as leakage current, sensitivity, signal linearity is measured to evaluate multi-layer radiation sensor material.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.330-330
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• 2007

Polycrystalline mercuric iodide $HgI_2$) films are being developed as a new detector technology for digital x-ray imaging. The $HgI_2$ is generally vacuum deposited by physical vapor deposition (PVD) process. But the PVD thick deposition has been caused any instability in the biasing due to any defects or cracks. In this work we present a new particle-in-binder (PIB) methodologies used for the $HgI_2$ thick films. These growth techniques can be easily extended to produce much larger film areas. This paper, for the first time, presents results and comparison of polycrystalline $HgI_2$ films derived by various PIB methods. We investigated the structural and morphological properties of the films using X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis. The films were characterized with respect to their electrical properties and in response to x-ray photons. Physical and electrical results were also compared between conventional polycrystalline PVD and our detectors. Leakage current as low as $350\;pA/cm^2$ at the bias voltage of ~ 200 V has been observed. And high sensitivity and good linearity in the response to x-rays was obtained in the film derived by PIB sedimentation method. Our future efforts will concentrate on optimization of film growth techniques for uniform large area deposition on image readout arrays.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.30 no.4 s.48
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• pp.543-548
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• 2004

For pearl pigments used for splendor or gloss effect of make-up products, especiallv point make-up products like eye-shadow and blusher, we studied the variation of particle size distribution by the grinding time and by the binder used as a binding agent. In this study. high speed mixer was used and the particle sire distribution was measured by using the light scattering method. In case of pearl pigments, its median diameter of $5{\;}{\mu}m$, the particle size was reduced to 4.6 um when it was ground for 120 s. When it was applied for the pearl pigment of $45{\;}{\mu}m$, the particle size was reduced to $27{\;}{\mu}m$. We confirmed that the latter was reduced more largely and the original gloss was reduced too. For the binder, we studied the correlation between particle size of raw material and grinding time. We also investigated the effects of the binder contents on the variation of particle size distribution of products by aggregation of particles.

• Korean Journal of Metals and Materials
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• v.48 no.5
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• pp.401-409
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• 2010

This study was performed to develop an antibacterial film that can be dried at room temperature. A nanosized TiO$_2$ particle-dispersed solution was prepared by the hydrothermal treatment of peroxo-titanic acid at 160${^{\circ}C}$ for 4h. The binder was synthesized through the hydrolysis and condensation reactions of TEOS (10cc) and GPTS (3.5cc) in the mixture of H$_2$O (30cc) and EtOH (30cc). The synthesized binder was mixed with 0.1 M of TiO$_2$ solution in a volume ratio of binder/TiO$_2$ solution=0.25~0.5. The glass substrate was coated after using the dip coating method, which was then followed by drying for over 2h at room temperature. Although the TiO$_2$ particles did not chemically-bond to the binder, the coating layer strongly adhered to the substrate and displayed good antibacterial properties.

• Journal of the Korean Society of Radiology
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• v.2 no.3
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• pp.19-25
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• 2008

Commercial analog x-ray detectors based on film cassettes have been showing problems such as with image storage and image transmission. Recently direct conversion material, photoconductor whit flat panel have been researched which generate the electron hole-pair (EHP). In this paper, we researched the electrical properties of the PbO and Lead(II) oxide PbO. film which fabricated by Particle-In-Binder(PIB) method. We compared tetragonal ${\alpha}$-PbO with orthorhombic ${\beta}$-PbO physical property. Tetragonal material was more than orthorhombic material in other paper. The solution was Poly Vinyl Butyral(PVB) in the PIB. We discussed about the sample of x-ray sensitivity, leakage current, Signal to Noise Rate and investigated SEM for the physical property of sample. We need to think more research ${\alpha}$-PbO material fabrication.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.254-255
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• 2005

In this paper, we investigated electrical characteristics of the X-ray detector of mercuric iodide (HgI2) film fabricated by PIB(Particle-in-Binder) Method on ITO substrates 17cm$\times$20cm in size with thicknesses ranging from approximately 200${\mu}m$ to 240${\mu}m$. In the present study, using I-V measurements, their electrical properties such as leakage current, X-ray sensitivity, and signal-to-noise ratio (SNR),were investigated. The results of our study can be useful in the future design and optimization of direct active-matrix flat-panel detectors (AMFPD) for various digital X-ray imaging modalities.

• Journal of the Korean Ceramic Society
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• v.29 no.9
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• pp.695-704
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• 1992

In (Pb, La)(Zr, Ti)O3 ceramic system, the functionally gradient material (FGM) was developed, and its processing and properties were investigated. The FGMs were successfully prepared through doctor blade method with acrylic binder system as well as mold stacking press method. The ultrasonic treatment was very effective for particle dispersion in slurry, and it lead to form clack-free green films. The strain-voltage characteristics of the FGM system was significantly improved which fabricated between a high piezoelectric-low dielectric and a low piezoelectric-high dielectric composition layer.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.72-72
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• 2009

본 연구에서는 Photoconductor materials 기반의 평판형 X-ray Detector film 제작에 관한 연구를 수행하였다. 기존의 광도전성 물질로 사용되어 오던 비정질 셀레늄(Amorphous seleinum; a-Se) 기반의 디지털 방사선 검출기 보다 높은 신호 및 동작 특성을 가지는 Mercury Iodide(HgI2)와 열적, 전기적 특성이 안정적이며, 소자의 동작특성이 우수한 Lead Oxide(PbO) 기반의 X-ray Detector film의 개발에 있어서 각각 HgI2 및 PbO 두 물질 층을 적정비율에 맞추어 제작함으로써 최적의 X-ray Detector를 구현하고자 하였다. 이는 빠른 영상획득을 통해 기존의 방식이 가지는 문제점을 해결하고 의료기기 디지털화를 구현할 수 있는 차세대 시스템을 개발하고자 하는 것이다. 본 연구에서는 기존의 진공증착법의 두꺼운 대면적 필름의 제조가 어려운 문제점을 해결하고자 Particle In Binder method(PIB) 방법을 이용하여 $3"{\times}3"$사이즈의 두께 $200{\mu}m$의 다결정의 Photoconductor 필름을 제조하여 전기적 특성을 평가하였다. 제작된 필름의 전기적 특성을 dark current, X-선 sensitivity와 SNR(Signal to -Noise Rate) 등을 측정하여 정량적으로 평가 하였다. 기준 실험으로 진행한 DG 2.1 바인더를 사용한 single-HgI2 층에서 보다 높은 sensitivity 값을 보였지만 높은 dark current로 인해 SNR이 떨어지는 결과를 볼 수 있었다. 본 연구에서 제시하는 두 Photoconductor material의 Soaking method를 이용한 실험에서는 single-HgI2에 해당하는 높은 sensitivity 및 저감된 dark current로 인해 높은 SNR 값을 획득하였다. 하지만 습도와 같은 주변 환경에 의한 재현성 문제로 인한 신호값의 불안정성에 대한 문제점도 남아 있으므로, 차후 최적화된 material 제작 공정을 위한 연구가 꾸준히 진행 되어져야 할 것이다.