• Title/Summary/Keyword: Pre-oxidation

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Influences of anodizing on improvement in reflection rate of aluminum surface (알루미늄 표면의 정반사율 향상에 미치는 양극산화의 영향)

  • Choi, Kyang-Kun;Kim, Dong-Hyoun;Kim, Hoon;Nam, In-Tak
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 2002.11a
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    • pp.207-211
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    • 2002
  • Anodizing film was prepared by anodic oxidation of pure aluminum(purity > 99.50) using DC power supply for constant current mode in an electrolytic solution of surface of sulfuric acid. Effects of pre-treatment process such as chemical polishing, acid cleaning, alkali etching before anodic oxidation, were studied to microstructures and surface morphologies. A roughness on surface of anodizing film had to be decreased for amorphous phase by anodic oxidation. A roughness on surface of anodizing film decrease as annealing temperature increased in chemical polishing.

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Low Temperature Catalytic Activity of Cobalt Oxide for the Emergency Escape Mask Cartridge

  • Park, Jae-Man;Kim, Deog-Ki;Shin, Chang-Sub
    • International Journal of Safety
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    • v.1 no.1
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    • pp.58-61
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    • 2002
  • A preparation method of cobalt supported alumina catalyst for a emergency escape mask cartridge has been studied. Catalysts were prepared by incipient wetness impregnation method using pre-shaped $\gamma$=alumina powders of 70-100 mesh. The catalyst was tested in a continuous-flow reactor system and characterized by elemental analysis, BET and TGA-DTA techniques. Cobalt shows higher activity than platinum or nickel for carbon monoxide oxidation at room temperature. Optimum loading amount of cobalt was 10 wt.% for CO oxidation and the reaction activity increases gradually with the increase of calcination temperature up to $450^{\circ}C.

A Study on the Hump Characteristics of the MOSFETs (MOSFET의 험프 특성에 관한 연구)

  • Kim, Hyeon-Ho;Lee, Yong-Hui;Yi, Jae-Young;Yi, Cheon-Hee
    • Proceedings of the Korea Information Processing Society Conference
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    • 2002.04a
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    • pp.631-634
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    • 2002
  • In this paper we improved that hump occurrence by increased oxidation thickness, and control field oxide recess$(\leq20nm)$, wet oxidation etch time(19HF, 30sec), STI nitride wet cleaning time(99 HF, 60sec + P 90min) and gate pre-oxidation cleaning time(U10min+19HF, 60sec) to prevent hump occurring at STI channel edge.

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Study of reflection rate character of anodized aluminum thin film (알루미늄 양극산화피막의 반사율 특성연구)

  • Kim, Seung-Kyum;Kim, Dong-Hyun;Joo, In-Joong;Nam, In-Tak;Kim, Hoon
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 2003.11a
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    • pp.227-232
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    • 2003
  • Anodizing film was prepared by anodic oxidation of pure aluminum(purity > 99.50) using DC power supply for constant current mode in an electrolytic solution of surface of sulfuric acid. Effects of pre-treatment process such as chemical polishing, acid cleaning, alkali etching before anodic oxidation, were studied to microstructures and surface morphologies. A roughness on surface of anodizing film had to be decreased for amorphous phase by anodic oxidation. A roughness on surface of anodizing film decrease as annealing temperature increased in chemical polishing.

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The MOSFET Hump Characteristics Occurring at STI Channel Edge (STI 채널 모서리에서 발생하는 MOSFET의 험프 특성)

  • 김현호;이천희
    • Journal of the Korea Society for Simulation
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    • v.11 no.1
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    • pp.23-30
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    • 2002
  • An STI(Shallow Trench Isolation) by using a CMP(Chemical Mechanical Polishing) process has been one of the key issues in the device isolation[1] In this paper we fabricated N, P-MOSFEET tall analyse hump characteristics in various rounding oxdation thickness(ex : Skip, 500, 800, 1000$\AA$). As a result we found that hump occurred at STI channel edge region by field oxide recess. and boron segregation(early turn on due to boron segregatiorn at channel edge). Therefore we improved that hump occurrence by increased oxidation thickness, and control field oxide recess( 20nm), wet oxidation etch time(19HF,30sec), STI nitride wet cleaning time(99HF, 60sec+P 90min) and fate pre-oxidation cleaning time (U10min+19HF, 60sec) to prevent hump occurring at STI channel edge.

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Effect of Sintering Temperature on the High Temperature Oxidation of Fe-Cr-Al Powder Porous Metal Manufactured by Electrospray Process (정전 분무법을 이용하여 제조된 Fe-Cr-Al 분말 다공체 금속의 고온 산화에 미치는 소결 온도의 영향)

  • Oh, Jae-Sung;Kong, Young-Min;Kim, Byoung-Kee;Lee, Kee-Ahn
    • Journal of Powder Materials
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    • v.19 no.6
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    • pp.435-441
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    • 2012
  • A new manufacturing process of Fe-Cr-Al powder porous metal was attempted. First, ultra-fine fecralloy powders were produced by using the submerged electric wire explosion process. Evenly distributed colloid (0.05~0.5% powders) was dispersed on PU (Polyurethane) foam through the electrospray process. And then degreasing and sintering processes were conduced. In order to examine the effect of sintering temperature in process, pre-samples were sintered for two hours at temperatures of $1350^{\circ}C$, $1400^{\circ}C$, $1450^{\circ}C$, and $1500^{\circ}C$, respectively, in $H_2$ atmospheres. A 24-hour TGA (thermo gravimetric analysis) test was conducted at $1000^{\circ}C$ in a 79% $N_2$+21% $O_2$ to investigate the high temperature oxidation behavior of powder porous metal. The results of the high temperature oxidation tests showed that oxidation resistance increased with increasing sintering temperature (2.57% oxidation weight gain at $1500^{\circ}C$ sintered specimen). The high temperature oxidation mechanism of newly manufactured Fe-Cr-Al powder porous metal was also discussed.

Treatment Efficiency of Complex Wastewater by Fenton's Oxidation Condition (펜톤산화에 따른 복합폐수의 처리효율연구)

  • Sung, Il-Wha
    • Journal of Environmental Health Sciences
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    • v.32 no.5 s.92
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    • pp.446-450
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    • 2006
  • In order to treat the wastewater containing organic compound, pre-treatment system connected with MSP(molecular separation process) was investigated. With the aim of selecting an optimum process of Fenton's oxidation, removal efficiency of each process in the optimum reaction condition was recommended. The $Fe/H_{2}O_{2}$(ferric sulfate to hydrogen peroxide)reagent is referred to as the Fenton's regent, which produces hydroxyl radicals by the interaction of Fe with $H_{2}O_{2}$. The powerful oxidizing ability and extreme kinetic reactively of the hydroxyl radical was well established. Increasing dosage of $Fe/H_{2}O_{2}$ increased removal efficiency as molar ratio of $Fe/H_{2}O_{2}$ between 0.2 and 2.5. Optimum dosage of molar ratio was 1. The removal efficiency for reaction condition was increased as pH decreased when the molar ratio of $Fe/H_{2}O_{2}$ was 1.7. Fenton's oxidation was most efficient in the reaction time 35 min for complex wastewater. Also, coagulation aid experiments using kaolin resulted in 3% of kaolin dosage.

Degradation Characteristics of Non-biodegradable Matters using Pre-Coagulation and Fenton Oxidation Process in Livestock Wastewater (전응집 및 Fenton 산화공정을 이용한 축산폐수의 난분해성물질 제거특성에 관한 연구)

  • Cho, Chang-Woo;Kim, Boung-Young;Chae, Soo-Choen;Kim, Sun-Ae;Chung, Paul-Gene
    • Journal of Korean Society on Water Environment
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    • v.22 no.1
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    • pp.66-73
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    • 2006
  • The purpose of this study was done to evaluate degradation characteristics of non-biodegradable organic matters including aromatic compounds in livestock wastewater using CFZ process. The CFZ process is consisted of coagulation/sedimentation, Fenton oxidation and zeolite adsoption process. degradation charateristics of each treatment water including livestock wastewater were analyzed by UV scanning, FT-IR and GC/MS. After coagulation/sedimentation process as 1st treatment, non-biodegradable matters remained after 1st treatment were removed by using OH radical produced in Fenton oxidation process. As a result of treatment using these processes, NBDCOD removal efficiency was over 90%. Increase of $E_2/E_3$ ratio (absorbance at 250 and 365 nm) in each treatment water means that aromaticity of livestock wastewater decreased. In case of GC/MS, most aromatics or polynuclear aromatics like benzene, phenol and scatol in livestock wastewater almost wasn't detected after oxidation using OH radical.

Improvement of Adhesion Strength between Cu-based Leadframe and Fpoxy Molding Compound

  • Lee, Ho-Yoing
    • Transactions on Electrical and Electronic Materials
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    • v.1 no.3
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    • pp.23-28
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    • 2000
  • A block-oxide layer was formed on the surface of Cu-based leadframe by chamical oxidation method in order to enhance the adhesion strength between Cu-based leadframe and epoxy molding compound (EMC) Using sandwiched double cantilever beam (SDCB) specimens, the adesion strength was measured in terms of interfacial fracture toughness, G$\sub$IC//Results showed that the black-oxide layer was composed of two kinds of layers: pebble-like Cu$_2$O layer and acicular CuO layer, At the initial stage of oxidation the Cu$_2$O layer was preferentially formed and thickened up to around 200 nm whithin 1 minute of the oxidation time. Then the CuO layer started to from atop of the Cu$_2$O layer and thickened up to around 1300 nm until 20 minutes. As soon as the CuO layer formed, the thickness of Cu$_2$O layer began to reduce and finally reached to around 150 nm. The pre-cleaned and the Cu$_2$O coated leadframes showed almost no adhesion of EMC, however, as the CuO precipitates appeared and became continuous, G$\sub$IC/ increased up to around 80 J/㎡. Further oxidation raised G$\sub$IC/ up. to around 100 J/㎡.

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