Abstract: Disclosed is a method of producing lithium sulfide (Li2S) without using hydrogen sulfide (H2S) gas. Particularly, the method of producing lithium sulfide (Li2S) includes preparing a starting material including a metal oxide by subjecting a mixed powder including an inorganic compound containing lithium and oxygen, a metal reducing agent, and sulfur (S) to synthesis reaction using mechanical force, preparing a mixed solution by mixing the starting material and a solvent, and obtaining a lithium sulfide (Li2S) powder by removing the metal oxide from the mixed solution and then performing drying.

Abstract: The present disclosure provides an EGR cooler for brazing joint including an inlet configured to form an inlet area through which intake air and recirculation exhaust gas are supplied, a heat exchange unit formed with a gas tube connected to the inlet and through which the supplied intake air and the recirculation exhaust gas pass, and an outlet configured to form an outlet area through which the intake air and the recirculation exhaust gas mixed by passing through the heat exchange unit are discharged, in which the inlet, the heat exchange, and the outlet are brazing-joined, and a guide pattern configured to guide the flow of a filler metal so that surface energy of the filler metal applied for brazing joint is increased is transferred to each joined area.

Abstract: Provided are stainless steel for a polymer fuel cell separator and a method of manufacturing the stainless steel, in which a surface modification technique based on wet processing is applied to a surface of stainless steel used for parts such as an anode and a cathode, etc., of a stack that generates electricity, thereby improving corrosion resistance and electric conductivity, and preventing moisture from being formed.