摘要:
A method of manufacturing yield ratio-controlled steel, including the steps of subjecting alloy steel to rolling or wire drawing, thus obtaining a bar material; performing a first heat treatment, in which the material is heated and maintained for a predetermined period of time at a first temperature ranging from Ac1 to Ac3 based on Ac1 and Ac3 transformation temperatures; and cooling the material to a second temperature ranging from Mf to Ms based on a martensite start temperature (Ms) and a martensite finish temperature (Mf), and performing a second heat treatment, in which the material is maintained at the second temperature for a predetermined period of time.
摘要:
Provided is a method of manufacturing a grain-refined aluminum-zinc-magnesium-copper alloy sheet, including manufacturing an aluminum alloy sheet from an aluminum-zinc-magnesium-copper alloy melt by twin-roll strip casting, primarily rolling the aluminum alloy sheet manufactured in step 1, cold rolling the aluminum alloy sheet manufactured in step 2, and performing a heat treatment on the aluminum alloy sheet manufactured in step 3, thereby reducing processing time and cost by using twin-roll casting. Since grain refinement and homogenization of the sheet manufactured by the twin-roll casting are maximized by sequentially performing warm rolling, cold rolling, and a heat treatment on the sheet, elongation may be improved.
摘要:
Disclosed is a (K,Na)NbO3 (abbreviated by “KNN”)-based single crystal ceramic. The KNN-based single crystal ceramic according to the present disclosure is formulated by (K0.5−x/2Na0.5−x/2−y□y/2Mx+y/2)Nb1−x/3+yO3, wherein M indicates a metal having a different valence from Na, and □ indicates a metal vacancy. The above formulated KNN-based single crystal ceramic allows compensating for the volatilization of Na in a growing grain due to the addition of M2+ ions, and substituting M2+ ions for Na+ ions to form metal vacancies, thereby making possible the single crystal growth.
摘要:
The present invention provides a method for manufacturing an aluminum electrode using a solution process and an aluminum electrode manufactured thereby. The manufacturing method includes the steps of: manufacturing an aluminum precursor solution for the solution processing using AlH3 as a basic material before forming aluminum; coating the aluminum precursor solution on a substrate through the solution process and drying the aluminum precursor solution; and forming a low work function aluminum electrode through a low-temperature baking process at the temperature of at most 150° C. The method for manufacturing the aluminum electrode according to the present invention improves a thermal defect of the electrode due to a high-temperature baking process, prevents excessive loss of raw materials, and can manufacture aluminum electrodes of various sizes with area ranging from small to large at relatively low costs and by a simple process under atmospheric pressure.
摘要:
A scaffold for hard tissue regeneration comprising an active ingredient for treating osteoporosis and a preparation method thereof. The scaffold for hard tissue regeneration is prepared by the steps of mixing a polyphenol-based natural substance containing Quercetein or Genistein involved in the activation of osteoblasts and osteoclasts and the biofunctional analog thereof with a ceramic scaffold material and molding the mixture at room temperature into a three-dimensional scaffold. The biofunctional material included in the scaffold above may be sustain-released slowly over the long period of time so that the osteoblast activity is directly improved and at the same time the osteoclast activity is suppressed in the course of bone regeneration, to have the effect of improving bone regeneration.
摘要:
The present invention relates to high-nitrogen duplex stainless steels with an excellent eco-index and pitting corrosion resistance, in particular, to providing duplex stainless steels with ferrite-austenite phases, including: 16.5-19.5 wt. % of chromium (Cr), 2.3-3.5 wt. % of molybdenum (Mo), 1.0-5.5 wt. % of tungsten (W), 5.5-7.0 wt. % of manganese (Mn), 0.35-0.45 wt. % of nitrogen (N), with a remainder of iron (Fe). The high nitrogen duplex stainless steels with excellent eco-index and pitting corrosion resistance according to the present invention use manganese (Mn) and nitrogen (N) to exclude or mostly substitute Ni, which increases price instability of the steel grades and environment burden, to result in enhancing economic efficiency, price stability and eco-friendliness.
摘要:
A fabrication method of thermoelectric materials using core-shell structured nano-particles and thermoelectric materials fabricated by the same are provided. The method includes preparing core-shell structured nano-particles having thermoelectric elements coated on the surface thereof (step 1); adding and mixing the prepared core-shell structured nano-particles of step 1, bismuth (Bi) salts, tellurium (Te) salts and a surfactant in a solvent (step 2); adding and dispersing a reducing agent in the mixture of step (step 3); and heating the mixture of step 3 in which reducing agent is added and dispersed (step 4). According to the present invention, thermoelectric materials, nano-phase is homogeneously dispersed inside of thermoelectric grain boundary, can be fabricated and if the fabricated materials are used after sintering and bulking, the thermoelectric materials are maintained in a state that the nano-particles remain in dispersed phase even after sintering.
摘要:
A method of manufacturing a cold-rolled magnesium alloy sheet for improving formability, including, (a) preparing a composite sheet which is composed of a main sheet made of magnesium alloy and a restrainer made of steel and functioning to suppress transverse plastic deformation (plastic deformation in a transverse direction) of the main sheet during a rolling process, (b) performing a cold-rolling of the composite sheet, and (c) separating the cold-rolled magnesium alloy sheet from the cold-rolled composite sheet obtained from (b). The magnesium alloy sheets manufactured by the invention has improved formability at an ambient temperature, and thus can be usefully applied to extensive industrial fields such as automobiles and aircrafts.
摘要:
The present invention relates to high-nitrogen duplex stainless steels with an excellent eco-index and pitting corrosion resistance, in particular, to providing duplex stainless steels with ferrite-austenite phases, including: 16.5-19.5 wt. % of chromium (Cr), 2.3-3.5 wt. % of molybdenum (Mo), 1.0-5.5 wt. % of tungsten (W), 5.5-7.0 wt. % of manganese (Mn), 0.35-0.45 wt. % of nitrogen (N), with a remainder of iron (Fe). The high nitrogen duplex stainless steels with excellent eco-index and pitting corrosion resistance according to the present invention use manganese (Mn) and nitrogen (N) to exclude or mostly substitute Ni, which increases price instability of the steel grades and environment burden, to result in enhancing economic efficiency, price stability and eco-friendliness.
摘要:
Disclosed is a method of manufacturing a super hard alloy containing carbon nanotubes, including (a) forming a carbon nanotube-metal composite from carbon nanotubes and metal powder, (b) mixing the carbon nanotube-metal composite obtained in (a) with hard-phase powder, (c) molding the powder mixture obtained in (b), and (d) sintering the molded body obtained in (c). In the method of the invention, the reaction between carbon nanotubes and transition metal carbide in the super hard alloy is minimized, thus maximizing an increase in toughness by virtue of the addition of carbon nanotubes, thereby obtaining the super hard alloy having both high hardness and high toughness. The super hard alloy containing carbon nanotubes manufactured using the method of the invention has high hardness and high toughness, and thus can be effectively utilized in cutting tools, molds, wear-resistant members, heat-resistant structural materials, etc.