Abstract:
저탄성상 기지상인 BN이나 흑연 또는 이들의 혼합물의 미립의 AIN, AIN/SiC, AlON 고탄성상 기지상에 균일하게 분산된 복합기지상과 상기 고탄성상 기지상과 동일 조성을 갖는 골재로 이루어진 AlN (질화 알루미늄)계 내화물 및 그의 제조방법. AlN-BN, AlN/SiC-BN, AlON-BN계의 AlN계 내화물의 제조 방법에 있어서 기지상을 이루는 AlN, AlN/SiC, AlON 미립 입자와 BN이나 흑연 또는 그 혼합물의 입자를 균일하게 혼합하고 이를 골재 입자 사이에 고르게 분포시키는 방법을 사용하여 기지상내에 존재하는 저탄성상 BN이나 흑연 또는 그 혼합물의 입자의 균일한 분포를 위하여 기지상을 구성하는 미립 입자와 BN이나 흑연 또는 그 혼합물 입자를 동시 분산하여 열분무 건조법에 의해 제조한 과립 상태로 첨가함으로써 내화물 내에서 전체적인 균일도를 유지함은 물론 기지상 내에서 BN 입자의 고른 분포를 얻을 수 있다.
Abstract:
본 발명은 일축 가압 소결 과정에서 기하 이방성을 가지는 휘스커의 이차원적 배향성을 축진시켜 기계적 물성과 공정 재현성이 우수한 휘스커 강화 세라믹스 복합 재료의 제조 방법을 제시하고 있다. 본 발명의 방법은 a)열처리한 SiC휘스커에 약 0.4~1.0 중량%의 중성 고분자 PVA를 첨가하여 PVA 흡착량을 최대로 중가시키고 분산성이 우수한 SiC휘스커 슬러리를 제조하는 단계, b)상기 SiC휘스커 슬러리를 pH4에서 형성한 세라믹스 기재상 슬러리와 혼합하여 동결 건조시켜 균일하고 소밀한 충전 구조를 갖는 과립을 준비하는 단계, 및 c)상기 과립을 가압 소결하는 단계로 이루어진다. 본 발명의 세라믹스 복합 재료는 740MPa의 가장 높은 평균 4점 굽힘 강도 및 약 20% 정도 중가된 파괴 인성을 가지며, 통상 발견되는 휘스커 결핍 부위와 같은 공정 결함이 없고 기계적 물성의 재현성이 향상된다.
Abstract:
The oxide composites comprise 60-95 wt.% cordierite and 5-40 wt.% celsian, and 60-90 wt.% cordierite, 10 wt.% celsian and 10-30 wt.% aluminum titanate. The composite material is produced by (a) mixing cordierite from the calcined starting materials at 600-800 deg.C for 2 hrs., with celsian by adding 0.1 mol% lithium carbonate to the source materials and firing them at 1,000-1,400 deg.C for 6 hrs., by dry process, (b) molding the cordierite-celsian mixture by isostatic pressing, (c) sintering it at 1,170-1,420 deg.C. In the case of cordierite-celsian-aluminum titanate composite, aluminum titanate is synthesized at 1,300-1,500 deg.C in the molar ratio of titania to alumina, 1:1 and added to the celsian and cordierite mixture.
Abstract:
The present invention relates to a method for manufacturing a nickel-based catalyst for steam carbon dioxide reforming reaction (SCR) of natural gas and, more particularly, to a method for manufacturing a nickel-based catalyst that is represented by Ni/η-Al_2O_3 manufactured by repeatedly impregnating nickel into a spherical eta-alumina support, which has many acid points formed thereon, and drying the impregnated product dozens of times, thus supporting the nickel at high density. A catalyst manufactured by the manufacturing method according to the present invention exhibits excellent catalytic activity even under the severe conditions of high temperature and high pressure when applied to steam carbon dioxide reforming reaction, and has little carbon deposited thereon owing to the excellent durability of the catalyst.
Abstract:
The present invention relates to an improved perovskite-based composite oxide catalyst in which a transition metal is dipped in order to improve the selectivity of hydrogen and remarkably decrease the selectivity of methane and carbon monoxide as byproducts. Moreover, the present invention relates to a method for selectively producing hydrogen by means of the C-H decomposition and C-O maintenance of glycerol using the metal oxide catalyst. The improved perovskite-based catalyst (NixMy/LaCexAl1-xO3) in which nickel and a second transition metal are dipped is applied to the reaction of glycerol so as to maintain the high conversion rate of glycerol and the high selectivity and yield of hydrogen. Accordingly, the catalyst can be usefully used as a catalyst for converting glycerol which is generated during a biodiesel process into high value-added hydrogen and as a catalyst for a reaction process of synthesizing high value-added hydrogen.
Abstract:
The present invention relates to a perovskite-type catalyst modified by means of Fe, a method for producing the same, and a method for producing a synthetic gas by means of simultaneous modification using the same. More specifically, the present invention relates to a natural gas vapor carbon dioxide hybrid modification catalyst having a perovskite structure in which La and Sr in an A-site and Ni and Fe in a B-site are substituted at a particular mole ratio. Moreover, the present invention relates to a method for producing a raw material for fischer-tropsch or methanol synthesis by producing a synthetic gas using the catalyst for hybrid modification. Compared to a catalyst for modification that is produced by existing impregnation techniques, the catalyst of the present invention shows a high carbon dioxide conversion rate and has remarkably decreased inactivity by carbon deposition so that the stability and activity of the catalyst can be ensured when reacted for a long time.