Korea Advanced Institute of Science and Technology

Soon-Hyung Hong

Seok-woo Jeon

Young-Soo Han

Dong-Ju Lee

Kwang-Hyun Park

Provided is a method of manufacturing a hexagonal boron nitride nanosheet to mass-produce a high-quality hexagonal boron nitride nanosheet at a low temperature in a safe process. The method of manufacturing a hexagonal boron nitride nanosheet includes (a) obtaining an alkali metal ion or alkali earth metal ion from a salt mixture including at least two kinds of alkali metal salt or alkali earth metal salt, (b) preparing a hexagonal boron nitride interlayer compound by inserting the alkali metal ion or alkali earth metal ion into layers of hexagonal boron nitride, and (c) obtaining a hexagonal boron nitride nanosheet by removing the alkali metal ion or alkali earth metal ion from the hexagonal boron nitride interlayer compound.

Method of forming high-quality hexagonal boron nitride nanosheet using multi component eutectic point system

The present invention provides a Fe--Mn--Cr--Al cryogenic alloy having high ductility, strength, toughness and corrosion-resistance, and a process for preparing the same. The cryogenic structural alloy of the invention is prepared by the steps of: air-induced melting of a metallic alloy composition which consists of Fe 48.6 to 64.7 wt %, Mn 25.0 to 35.0 wt %, Cr 10.0 to 13.0 wt %, Al 0.1 to 2.0 wt %, C 0.1 to 0.4 wt % and Si 0.1 to 1.0 wt %; hot-rolling of the melted alloy at 1,090.degree. to 1,110 .degree. C.; and, solution heat treatment of the hot-rolled alloy at 1,040.degree. to 1,060.degree. C. for 50 to 70 minutes. A cryogenic structural alloy of the invention has corrosion-resistance similar to that of conventional 304 stainless steel, higher strength, elongation and toughness than 304 stainless steel, and much higher elongation, corrosion-resistance and toughness than 9% Ni steel; and, therefore, it can be applied for LNG-related facilities including storage tanks, transporting pipes and valves, and transport ships, etc.

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Daejoen, South Korea

Soon-Hyung Hong