• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
• /
• pp.182-183
• /
• 2008

본 연구에서는 유전 손실이 낮고, 고분자(LCP)의 유전율을 높이기 위하여 (100-x)LCP(polymer)-xNPO(ceramic) 복합체 (x= 0, 10, 20, 30, 40, 50)의 유전 특성 및 미세구조를 연구하였다. LCP와 ceramic filler(NPO)는 Brabender Mixer를 사용하여 $300^{\circ}C$에서 혼합한 후, Hot press 사용하여 $300^{\circ}C$, 7ton 성형 압력으로 pellet 형태 $(2.5cm\times2.5cm\times0.1cm)$로 제조 하였다. LCP-NPO 복합 소재를 SEM을 통해 미세구조를 관찰하였고, 복합체의 유전 특성을 조사하였다.

• 한국산학기술학회논문지
• /
• 제7권5호
• /
• pp.771-777
• /
• 2006

최근 자동차에까지 환경친화적인 제품을 의무화하는 규제가 증가하고 있어 전구에 사용되는 납땜을 용접으로 대체하기 위한 연구가 필요하게 되었다. 본 연구에서는 기존의 측면 스폿용접의 문제점을 파악하여 TIG 제살용접공정을 개발하였고 용접시 깨지기 쉬운 유리부의 용접을 위해 세라믹 구조물을 개발하였다. 또한 바닥부 구멍을 메울 수 있도록 기존 바닥부 용가재 용접의 단점을 보완하여 최적 공정 파라미터를 선정하였다. 마지막으로 전구 수명 시험과 내진성 평가를 실시하여 용접된 제동등의 신뢰성을 확인할 수 있었다.

• 한국결정성장학회지
• /
• 제17권3호
• /
• pp.102-107
• /
• 2007

인산염계 유리를 사용하여 PDP 소자의 하판유전체 후막을 제작하였다. 유전체 후막의 제조는 soda-lime glass위에 silk screen printing 법을 사용하였다. 기판과 유전체후막의 열팽창계수를 맞추기 위하여 $TiO_2$와 $Al_2O_3$를 충진제로 사용하였다. 유전체의 결정화 거동은 DTA, XRD를 사용하였으며 광학적 열적 전기적인 특성을 알아보기 위하여 UV-spectrometer, Dilatometer, Impedance Analyser를 사용하였다. 실험결과 주 결정상은 메타인산아연과 피로인산아연으로 나타났다. $TiO_2$의 첨가로 인하여 반사율은 높아졌으나 상대적으로 유전상수는 높아졌다. 또한 $Al_2O_3$를 첨가한 경우 반사율은 크게 변화가 없었으나 유전상수 값은 낮아졌다. 또한 열팽창 계수는 약 $62{\times}10^{-7}/^{\circ}C$ 정도였다.

• 한국재료학회지
• /
• 제22권11호
• /
• pp.604-608
• /
• 2012

Recently, inorganic-organic hybrid materials have attracted much attention not only for their excellent thermal conductivity but also for their flame retardant properties. In this study, the properties of organic-inorganic hybrid insulating materials using inorganic fillers and polyurethane foam with different foaming conditions have been investigated. The addition of 1.5 wt% water to polyurethane as foaming agent shows the best foaming properties. The pore size was decreased in the foaming body with increasing of the $CaCO_3$ addition. The apparent density and thermal conductivity were increased by increasing the $CaCO_3$ addition. With an increasing amount of $CaCO_3$ powder, the flame retardant property is improved, but the properties of thermal conductivity and apparent density tend to decrease. When the addition of fine particles of $CaCO_3$, the apparent density and thermal conductivity were increased and, also, with the addition of coarse particles over $45{\mu}m$ in size, the apparent density and thermal conductivity were increased as well. In this study, the adding of $CaCO_3$ with average particle size of $27{\mu}m$ led to the lowest thermal conductivity and apparent density. After evaluation with different inorganic fillers, $Mg(OH)_2$ showed the highest thermal conductivity; on the other hand, $CaCO_3$ showed the lowest thermal conductivity.

• 한국재료학회지
• /
• 제27권1호
• /
• pp.12-18
• /
• 2017

Transparent organic-inorganic hybrid hard coating films were prepared by the addition of $SiO_2$ or $ZrO_2$, as an inorganic filler to improve the hardness property, filler was highly dispersed in the acrylic resin. To improve the compatibility in the acrylic resin, $SiO_2$ or $ZrO_2$ is surface-modified using various silanes with variation of the modification time and silane content. Depending on the content and kind of the modified inorganic oxide, transparent modified inorganic sols were formulated in acryl resin. Then, the sols were bar coated and cured on PET films to investigate the optical and mechanical properties. The optimized film, which has a modified $ZrO_2$ content of 4 wt% markedly improved in terms of the hardness, haze, and transparency as compared to neat acrylate resin and acrylate resin containing modified $SiO_2$ content of 8 wt%. Meanwhile, the low transparency and high haze of these films slowly appeared at $SiO_2$ content above 10 wt% and $ZrO_2$ content of 5 wt%, but the hardness values were maintained at 2H and 3H, respectively, in comparison with the HB of neat acrylate resin.

• 한국재료학회지
• /
• 제16권5호
• /
• pp.285-291
• /
• 2006

Copper powders have been widely used in electrically conductive coatings, electrode materials et al. and are very prospective since they are cheaper than noble metal powders such as silver or palladium. In this study, copper powders for metal filler of EMI shielding have been prepared using a solvothermal process from $CuSO_4$, NaOH, Glucose, mixed solvent ($H_2O$: Ethanol) and hydrazine which was used as a reducing agent at various reaction conditions. The prepared copper powders showed finely dispersed spherical shape without agglomerate, uniform morphology, narrow size distribution, high purity and were about 400-700 nm in size. The prepared powders were characterized using XRD, SEM, TGA, XPS, particle size measurement and EMI shielding efficiency.

• 한국세라믹학회지
• /
• 제49권1호
• /
• pp.100-104
• /
• 2012

Barium zincoborate (BZB) glass was added to $Ba_{0.5}Sr_{0.5}TiO_3$, and sintered at $875^{\circ}C$ for 2 h in air. When the BZB glass was added in quantities ranging from 15 to 20 wt%, the relative bulk density ranged from 93.1% to 94.2%, while the density decreased to roughly 81% thereafter up to 30 wt% glass addition. Quantitative XRD analysis showed that the $Ba_{0.5}Sr_{0.5}TiO_3$ filler was significantly dissolved into the BZB glass. However, no secondary phase was identified by XRD up to 30 wt% glass addition. The dielectric constant was about 130 to 140 at 1MHz up to 20 wt% BZB glass addition, while it decreased to about 60 thereafter, which may be ascribed to decreased density, partial dissolution of the $Ba_{0.5}Sr_{0.5}TiO_3$, and associated changes in the glass composition. The dielectric loss of the 20 wt% glass added specimen was 0.008.

• 한국응용과학기술학회지
• /
• 제18권2호
• /
• pp.153-159
• /
• 2001

Due to its low density, good mechanical properties and chemical inertness, glassy carbon(GC) has been studied for appications in several fields. A raw thermosetting resin of furanic resin was polymerized with a curing agent of p-toluenesulfonic acid monohydrate. The maximum yield of GC was obtained at the curing agent content of 1.0 wt% in furanic resin. In order to make thick GC, the affect of graphite filler addition to the furanic resin was investigated. The density and electrical resitivity of GC after graphitization were 1.45 $g/cm^{3}$ and 47 ${\times}10^{-4}$ ${\Omega}$ ${\cdot}$ cm respectively and the amorphous structure of GC was confirmed by XRD profiles with very broad peaks comparable to those of graphite at $206^{\circ}$ and $45^{\circ}$.

• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
• /
• pp.725-727
• /
• 2009

Lowering the dielectric constant is one of the important issues for the efficiency and the power consumption in the plasma display panel (PDP) industry. This study examined the effect of the addition of ceramic filler (up to 10% of crystalline and amorphous silica, respectively) to a $B_2O_3$-ZnO- $P_2O_5$ glass matrix on the dielectric, coefficient of thermal expansion, etching behaviors and residual stress for the barrier ribs in plasma display panels. The dielectric constant of barrier ribs is affected by containing two types of $SiO_2$ filler for the barrier rib composition in PDP.

• 한국분말재료학회지
• /
• 제16권6호
• /
• pp.431-437
• /
• 2009

Various inorganic fillers improve the thermal conductivity and physical properties of organic products. Alumina has been used a representative filler in the heat radiation sheet for the heat radiation of electric device. The high filling rate of alumina increases the thermal conductivity and properties of products. We successfully developed the spherical alumina by flame fusion process using the oxygen burner with LPG fuel. In the high temperature flame (2500$\sim$3000$^{\circ}C$) of oxygen burner, sprayed powders were melting and then rotated by carrier gas. This surface melting and rotation process made spherical alumina. Especially effects of chemical composition and particle size of stating materials on the melting behavior of starting materials in the flame and spheroidization ratio were investigated. As a result, spheroidization ratio of boehmite and aluminum hydroxide with endothermic reaction of dehydration process was lower than that of the sintered alumina without dehydration reaction.