• Korean Journal of Materials Research
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• v.8 no.11
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• pp.1005-1010
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• 1998

실험계획법을 이용하여 유리분말의 소결시 그 기공량에 영향을 미치는 각종 소결조건의 영향을 정량적으로 조사하였다. 본 실험범위내에서 결합제 유리의 총기공량, 개기공량 그미고 폐기공량은 모두 소결온도에 의해 가장 큰 영향을 받고 그 다음으로 소결온도에서의 유지시간에 의해 영향을 받으며 승온속도의 경우 그 영향이 상대적으로 미미함을 확인할 수 있었다. 이러한 결과들로부터 실제공정에 있어 승온속도보다는 다른 소결인자, 특히 소결온도를 조절하는 것이 결합제 유리의 기공량 조절에 가장 중요하리라 판단되며 실험계획법을 이용함으로써 보다 정확한 공전조건을 모색할 수 있었다.

• Proceedings of the KIEE Conference
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• 1994.07b
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• pp.1271-1273
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• 1994

In the field of the optics, precise machine, semiconducting processing, the micro-positioning actuators are required for the control of position in the submicron range. In this study, PNN-PZN-PZT ceramics were fabricated by solid state reaction. The structural, dielectric and electric properties were investigated for sintering condition. The specimen sintered for 1hr at 1,150($^{\circ}C$), had the highest density and dielectric contant.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.8
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• pp.603-611
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• 2020

A porous material which can contain liquid perfume was manufactured by adding 1~4 wt% of polysiloxane into a composite containing 20 ㎛ Ag powder and 30 wt% of 53 ㎛ salt, sintering for 60 min at 750℃, and melting salt selectively. The changes in pore, hardness, and microstructure were confirmed according to the polysiloxane content both before and after sintering. The manufactured silver liquid container was formed with open pores both before and after sintering, and the container shrunk by 2~7 % in both perpendicular and parallel directions after sintering. Vickers hardness was increased after sintering and was doubled when 2 wt% of polysiloxane was added. In case of the microstructure, the surface condition of the silver liquid container became darker according to the polysiloxane content, and the pore size was decreased from 50 ㎛ to under 10 ㎛. The composition distribution result revealed an even distribution when 2 wt% of polysiloxane was added but uneven distribution when over 3 wt% of polysiloxane was added due to decreased hardness by cluster. Therefore, the addition of an appropriate amount of 2 wt% polysiloxane reinforced the porous silver with open pores to offer application for jewelry usage.

• Applied Chemistry for Engineering
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• v.8 no.2
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• pp.292-300
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• 1997

In this study PZT powders were prepared with shapes of cubic by hydrothermal synthesis with various starting materials, and the sintering characteristics of the powders were investigated. The particle shapes were cubic regardless of starting materials, but the mean size of particles formed using $Pb(NO_3)_2$, $Ti(OC_4H_9)_4$ and $Zr(OC_4H_9)_4$ was relatively smaller than that of particles prepared from other starting materials. Agitation of the feedstock during hydrothermal reaction results in decreasing the required reaction temperature for the formation of nuclei, and in increasing the size of product particles. XRD results showed that the major phase of PZT crystal powders was a tetragonal phase at the Zr to Ti ratio of 40 to 60, or a rhombohedral phase at its ratio of 60 to 40. The density of a sintered body made from the hydrothermal powders in PbO surrounding varied with sintering temperatures and with periods of sintering time. The experimental results also showed that the optimum sintering condition was at $1150^{\circ}C$ for a 2hr sintering, and that the density of a sintered body was $7.6g/cm^3$.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.8 no.4
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• pp.667-672
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• 1998

Pyroelectric properties of $Pb(Mg_{1/3}Nb_{2/3})O_3-PbTiO_3$ ceramics prepared by the columbite precursor method have been investigated as a function of the sintering temperature in the range of $1000^{\circ}C$ to $1250^{\circ}C$. The $Pb(Mg_{1/3}Nb_{2/3})O_3-PbTiO_3$ ceramics show typical relaxor ferroelectric behavior. The optimum condition for obtaining samples with high densities and improved pyroelectric properties occur at a sintering temperature of $1250^{\circ}C$ and sintering times of 2 hours. The $Pb(Mg_{1/3}Nb_{2/3}O_3-PbTiO_3$ ceramics show the possibility for pyroelectric sensors with pyrostat.

• Journal of the Korean Ceramic Society
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• v.16 no.1
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• pp.31-37
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• 1979

The middle point of composition within the system $MgO-Al_2O_3-SiO_2$ has been studied for applicability as ceramics dielectrics. A Kyul Sung Tale of high purity, magnesia clinker of Sam-wha chemical company, C.P. aluminium oxide, calcium carbonate, red lead, barium carbonate which was made into frit were used the raw materials. A number of steatite ceramics were prepared under carefully controlled condition and the water absorption, linear shrinkage, power factor, dielectric constant and dielectric loss were measured at elevated temperature. When we used magnesia clinker as flux, the quantity of this flux was 0.05mole, sintering temperature was continued for 2 hrs. at 1, 27$0^{\circ}C$. From this conditions, we could get the data whose power factor was 0.142%, water absorption was zero, linear shrinkage was 8.76%, dielectric constant was 5.63, dielectric loss was 0.00799. When we used red lead as flux, the quantity of this flux was 0.033mole and 0.066mole, sintering temperature was continued for 2hrs. at 1, 26$0^{\circ}C$. From this conditions, we could get the data whose water absorption was zero, linear shrinkage was 8.03%, and 8.48%, power factor was 0.136% and 0.062%, dielectric loss was 0.0072 and 0.0037. When we used barium carbonate made into frit as flux, the quantity of this flux was 0.02mole, sintering temperature was continued for 2hrs. at 1, 27$0^{\circ}C$. From this conditions, we could get the data whose water absoption was zero, linear shrinkage was 8.44%, power factor was 0.138%, dielectric constant was 5.69, dielectric loss was 0.0074.

• Journal of the Korean Society for Nondestructive Testing
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• v.34 no.5
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• pp.377-383
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• 2014

An addressable conducting network (ACN) makes it possible to monitor the condition of a structure using the electrical resistance between electrodes on the surface of a carbon fiber reinforced plastics (CFRP) structure. To improve the damage detection reliability of the ACN, the contact resistances between the electrodes and CFRP laminates needs to be minimized. In this study, silver nanoparticle electrodes were fabricated via printed electronics techniques on a CFRP composite. The contact resistance between the silver electrodes and CFRP were measured with respect to various fabrication conditions such as the sintering temperature of the silver nano-ink and the surface roughness of the CFRP laminates. The interfaces between the silver electrode and carbon fibers were observed using a scanning electron microscope (SEM). Based on this study, it was found that the lowest contact resistance of $0.3664{\Omega}$ could be achieved when the sintering temperature of the silver nano-ink and surface roughness were $120^{\circ}C$ and 0.230 a, respectively.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.381-384
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• 2008

The artificial lightweight aggregate was manufactured using stone-dust(SD) and bottom ash(BA) from crushed aggregate manufacture process and thermoelectric power plant respectively. The properties of artificial lightweight aggregate according to mixing ratio of SD and BA was that the density was decreased and the absorption was increased with increasing BA content, because bottom ash was contained many unburned carbon and $Fe_2O_3$ which generates gas by oxidation during a sintering process. The appropriate mixing ratio of SD and BA was estimated at about 5:5. The properties of artificial lightweight aggregate according to addition flux admixture was that it had lower density with increasing of $Na_2SO_4$ content. In this study, we could developed the artificial lightweight aggregate as the bulk density was $1.52g/cm^3$ and water absorption 7.3% under the condition that mixing ratio of SD:BA was 5:5, $Na_2SO_4$, $Fe_2O_3$ 1%, sintering temperature $1,150^{\circ}C$ and sintering time 15mins.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.549-552
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• 2008

The cement is accomplished with CaO, SiO2, Al2O3 and Fe2O3, etc. After pulverizing materials of the limestone, the sand and the clay(shale), iron ore, the cement becomes clinker materials sintering from the rotary kiln of oxidizing atmosphere. The part in the materials of the clinker is substituted with slag, sludge etc. and it is used. because The chromium which is to be included in the clinker materials, in sintering process hexavalent chromium is converted with the chrome. Consequently it changed the type and a content of clinker materials and test hexavalent chromium of the clinkers which is manufactured.

• Journal of the Korean Ceramic Society
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• v.44 no.12
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• pp.696-702
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• 2007

The family of (Sr,Mg)-doped $LaGaO_3$ compounds, which exhibit high ionic conductivity at $600-800^{\circ}C$ over a wide range of oxygen partial pressure, appears to be promising as the electrolyte for intermediate temperature solid oxide fuel cells. Conventional synthesis routes of (Sr,Mg)-doped $LaGaO_3$ compounds based on solid state reaction have some problems such as the formation of impurity phases, long sintering time and Ga loss during high temperature sintering. Phase stability problem especially, the formation of additional phases at the grain boundary is detrimental to the electrical properties of the electrolyte. From this point of view, we focused to synthesize single phase (Sr,Mg)-doped $LaGaO_3$ electrolyte at the stage of powder synthesis and to apply relatively low heat-treatment temperature using novel synthesis route based on combustion method. The synthesized powder and sintered bulk electrolytes were characterized by XRD, TG-DTA, FT-IR and SEM. AC impedance spectroscopy was used to characterize the electrical transport properties of the electrolyte with the consideration of the contribution of the bulk lattice and grain boundary to the total conductivity. Finally, relationship between synthesis condition and electrical properties of the (Sr, Mg)-doped $LaGaO_3$ electrolytes was discussed with the consideration of phase analysis results.