• Journal of Power System Engineering
• /
• v.18 no.3
• /
• pp.14-19
• /
• 2014

The purpose of the study is to investigate the effect of additive catalyst according to the thermal aging of vanadia SCR catalysts. At a fresh condition, the $3V_2O_5-5WO_5-92TiO_2$ SCR showed the highest NOx conversion rate of about 30%, the performance of 5 kinds of SCR to which additive catalysts were added was not improved due to the insignificant effect of acid site control. For catalysts aged for 12h at $700^{\circ}C$, the SCR to which 3wt% Zeolite was added decreased in NOx conversion rate by 2.5% on average compared to the fresh SCR, it showed higher thermal durability than other additive catalyst. For 3Zeolite with high performance of NOx conversion rate during thermal aging, the Zeolite with stronger durability at a high temperature than other 5 kinds of SCR catalysts decreased the sintering of catalysts.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2000.10a
• /
• pp.386-391
• /
• 2000

It is known that Si$_3$N$_4$ceramic insert has less hardness than A1$_2$O$_3$ceramic insert. But Si$_3$N$_4$ceramic insert has not only high toughness and strength but also low thermal expansion coefficient, which makes it has longer tool life under thermal stress condition. In this study, commercial Si$_3$N$_4$ ceramic insert and home-made SiC-Si$_3$N$_4$ceramic insert which has different sintering time and chemical composition is tested under various cutting conditions. The experimental result is compared in terms of tool life and cutting force. Generally, As the cutting speed and the feed rate increased, the cutting force and the flank wear increased too. The performance of SiC-Si$_3$N$_4$ceramic insert shows the possibility to be a new ceramic tool.

• Journal of Powder Materials
• /
• v.9 no.2
• /
• pp.103-109
• /
• 2002

To investigate the fabrication possibility of a polymer particle dispersed metal matrix composite, polytetrafluorothylene (PTFE) particles were incorporated into the Al by the powder metallurgy process. The characteristics of a PTFE/Al composite were evaluated by measuring the density and hardness, and analysis of XRD, FT-Raman and microstructure. And wear properties of these composites were evaluated under the dry wear condition. It was possible to obtain the PTFE particles stably dispersed Al matrix composites by the hot press process at the sintering temperature of $500^{\circ}C$. The wear coefficient of a PTFE/Al compoite decreased with increasing of the volume fraction of PTFE. The wear weight of a PTFE/Al composite increased with increasing of the volume fractionof PTFE in the range of 0~10 vol.%PTFE, and showed maximum value at 10 vol.%PTFE, and then decreased at 20vol.%PTFE.

• Journal of the Korean institute of surface engineering
• /
• v.40 no.3
• /
• pp.131-137
• /
• 2007

The typical MCFC (molten carbonate fuel cell) anode is made of Ni-10%Cr alloy. The work of this paper is focused concerning long life of anode because Ni-10% Cr anode is suffering from sintering and creep behavior during cell operation. Therefore, Ni-coated Alumina powder($20{\mu}m$) was developed by electroless nickel plating. Optimum condition of electroless nickel coation on $20{\mu}m$ alumina is as follows: pH 11.7, temperature $65{\sim}80^{\circ}C$, powder amount $100cm^2/l$. The deposition rate for Ni-electroless plating was as a function of temperature and activation energy was evaluated by Arrhenius Equation thereby activation energy calculated slope of experimental data as 117.6 kJ/mol, frequency factor(A) was $6.28{\times}10^{18}hr^{-1}$, respectively.

• Transactions of the Society of Information Storage Systems
• /
• v.2 no.4
• /
• pp.236-239
• /
• 2006

Glass micro molding process is the most suitable process for fabricating high precision glass microlens amy at low cost. A new glass micro molding process was proposed. Tungsten carbide mold was fabricated by imprinting and sintering process to overcome the difficulties of the conventional process. In the glass micro molding process, process conditions such as processing temperature and compression force were changed. Geometrical properties of the replicated glass microlens array were measured and compared at variety process conditions. The condition of glass micro molding process was optimized. The experimental result showed that developed process was effective to produce a glass microlens array.

• Proceedings of the KIEE Conference
• /
• 1994.07b
• /
• pp.1409-1412
• /
• 1994

The electrodes for Phosphoric Acid Fuel Ceil were fabricated as a condition of PTFE contents in electrocatalyst layer and sintering temperature in the range of 25 -- 65 wt% and 310 -- $390^{\circ}C$, respectively. For the fabricated electrode, the accelation testing of cathode half cell at open circuit potential was investigated. While the performance of electrode showed maximum at the low level of PTFE contents in the initial stage of accelation testing, the maximum performance was shifted to higher PTFE contents of 45wt% after 24hrs accelation testing.

• Proceedings of the Korean Powder Metallurgy Institute Conference
• /
• 2006.09b
• /
• pp.754-755
• /
• 2006

In order to develop the SUS304L housing by powder metallurgy for an optical device useful for the FTTH communication system, the optimum compacting pressure and sintering temperature were investigated using granulated powder as the material to satisfy high air-tightness and high laser-weldability. Then the laser-welding test of specimen made under the optimum condition was carried out to observe welding sputters.

• Journal of the Korean Ceramic Society
• /
• v.43 no.9 s.292
• /
• pp.515-518
• /
• 2006

The microstructure of $ZrO_2$ toughened $Al_2O_3$ ceramics was carefully controlled so as to obtain dense and fine-grained ceramics, thereby improving the properties and reliability of the ceramics for capillary applications in semiconductor bonding technology. $Al_2O_3-ZrO_2(Y_2O_3)$ composite was produced via Ceramic Injection Molding (CIM) technology, followed by Sinter-HIP process. Room temperature strength, hardness, Young's modulus, thermal expansion coefficient and toughness were determined, as well as surface strengthening induced by the fine grained homogenous microstructure and the thermal treatment. The changes in alumina/zirconia grain size, sintering condition and HIP treatment were found to be correlated.

• Journal of the Korean Ceramic Society
• /
• v.28 no.1
• /
• pp.67-73
• /
• 1991

Monodispersed PZT fine particles were obtained from the condition which 0.2Pb (OC3H7)2/EtOH, 0.108Zr(OC4H9)4/EtOH and 0.092 Ti (OC2H5)4/EtOH were refluxed for 5 hrs at 76$^{\circ}C$ and hydrolyzed with 0.1-0.4 H2O/EtOH. The monodispersed particle was amorphous and crystallized to the tetragonal PZT phase when heated at $600^{\circ}C$. Particle size was about 0.55${\mu}{\textrm}{m}$ in 0.3 H2O/EtOH and 0.3${\mu}{\textrm}{m}$ in other cases. Relative density of sintered body at 90$0^{\circ}C$ and 100$0^{\circ}C$ was 93.5% and 98%, respectively.

• Journal of the Korean Ceramic Society
• /
• v.28 no.3
• /
• pp.225-233
• /
• 1991

In this study, we tried to find out the appropriate synthetic condition and magnetic properties of Ni-Zn ferrite {(NixZn1-x)Fe2O4} powders (where X=0, 0.1, 0.2, 0.3, ……0.9, 1). Ferrite powders were prepared by wet-direct method at 86℃ for 6hrs from FeCl36H2O, NiCl26H2O, and ZnCl2. The powders of (NixZn1-x)Fe2O4 (where X=0.4, 0.5, 0.6) have a good crystallinity, but the other ferrite powders consist of crystal and precursor ferrite. The ferrite powder's lattice constant is increased when ratio of ZnO contant is increased in the ferrite composition. And initial permeability was measured after sintering, result indicated regular pattern except (Ni0.4Zn0.6)Fe2O4 when the frequency were changed 10KHz to 10MHz.