• Title/Summary/Keyword: $Ni_3$Al

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The Effect of LiBr Concentration on Corrosion of Absorption Refrigeration Systems Using $LiBr-H_2O$ Working Fluids ($LiBr-H_2O$계 흡수식냉동기의 부식에 미치는 LiBr 농도의 영향)

  • Lim Uh Joh;Jeong Ki Cheol
    • Journal of the Korean Institute of Gas
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    • v.5 no.4 s.16
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    • pp.33-39
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    • 2001
  • This paper was studied on corrosion behavior of absorption refrigeration systems using $LiBr-H_2O$ working fluids. In the various concentration of lithium bromide solution, polarization test of SS 400, Cu(C1220T-OL) and Al-Ni bronze is carried out. And the corrosion behavior of materials forming absorption refrigeration systems is investigated. The main results are as following: 1) As concentration of lithium bromide solution increases, polarization resistance of materials of each kinds is low. And open circuit potential becomes less noble, the corrosion current density is high drained 2) Open circuit potential of SS 400 is less noble than that of Cu and Al-Ni bronze, corrosion current density of SS5 400 is high drained than that of Cu and Al-Ni bronze. 3) Anodic polarization of Cu and Al-Ni bronze in $62\%$ LiBr solution continues the active state. that of Cu and Al-Ni bronze in the natural sea water maintains the active state and the critical current for passivation appears.

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Study of the Optimal Calcination Temperature of an Al/Co/Ni Mixed Metal Oxide as a DeNOx Catalyst for LNT

  • Jang, Kil Nam;Han, Kwang Seon;Hong, Ji Sook;You, Young-Woo;Suh, Jeong Kwon;Hwang, Taek Sung
    • Clean Technology
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    • v.21 no.3
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    • pp.184-190
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    • 2015
  • Most of LNT catalysts use noble metals such as Pt for low temperature NOx oxidation but there is an economic weakness. For the purpose of overcoming this, this study is to develop DeNOx catalyst for LNT excluding PGM (platinum group metal) such as Pt, Pd, Rh, etc. To do so, Al/Co/Ni catalyst selected as a preliminary test is used to study fundamental property and NOx’s conversion according to calcined temperature. Ultimately, that is, Al/Co/Ni mixed metal oxide which does not use PGM is selected and physicochemical characterization is performed by way of XRD, EDS, SEM, BET and ramp test and NOx conversion is also analyzed. This study shows that all samples consist of mixed oxides of spinel structure of Co2AlO4 and NiAl2O4 and have enough pore volume and size for redox. But as a result of NH3-TPD test, it is desired that calcined temperature needs to be maintained at 700 ℃ or lower. Also only samples which are processed under 500 ℃ satisfied NO and NOx conversion simultaneously through ramp test. Based on this study’s results, optimum calcined temperature for Al/Co/Ni=1.0/2.5/0.3 mixed metal oxide catalyst is 500 ℃.

The Characterization of Nano-Nickel Catalyst with High Activity by Mechanochemical (MC) Method I. Microstructure of MA Ni-50wt% Al and Preparation of Nano-Ni (기계.화학적 방법으로 제조된 고활성 나노-니켈 촉매의 특성 I. MA된 Ni-50wt% Al 합금의 미세구조 및 나노 촉매 제조)

  • Lee, Chang-Rae;Choe, Jae-Ung;Gang, Seong-Gun
    • Korean Journal of Materials Research
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    • v.9 no.6
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    • pp.615-621
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    • 1999
  • The new process in order to fabricate of Ni catalyst with high activity by the mechanochemical(MC) method which was combined the mechanical alloying(MA) and the chemical treatment process. The microstructure and characterization of mechanically alloyed Ni-5-wt% Al powder and Ni catalyst gained by alkali leaching were investigated byt he various analysis such as XRD, SEM-EDS, HRTEM and laser particle analyzer. The steady state powder with 1~2$\mu\textrm{m}$ mean particle size was obtained after 30hr milling with the PCA of 2 wt% stearic acid under the condition of grinding stainless steel ball to powder ratio of 60:1 and rotating speed fo 300rpm. According to result of HRTEM diffraction pattern, MA powder of the steady state was nanocrystalline $Al_3$$Ni_2$ intermetallic compound. Ni catalyst was obtained after KOH leaching of the steady state powder was about 20nm nanocrystalline which contained about 8 wt % Al.

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