Abstract: The invention provides a super hard and tough, nano-crystal austenite steel bulk material having an improved corrosion resistance, and its preparation process. The austenite steel bulk material comprises an aggregate of austenite nano-crystal grains containing 0.1 to 2.0% (by mass) of a solid solution type nitrogen, wherein an oxide, nitride, carbide or the like of a metal or semimetal exists as a crystal grain growth inhibitor between and/or in said nano-crystal grains. For preparation, fine powders of austenite steel-forming components, i.e., iron and chromium, nickel, manganese, carbon or the like are mixed with a substance that becomes a nitrogen source. Mechanical alloying (MA) is applied to the mixture, thereby preparing nano-crystal austenite steel powders having a high nitrogen concentration. Finally, the austenite steel powders are consolidated by sintering by means of spark plasma sintering, rolling or the like.

Abstract: The invention provides a super hard and tough, nano-crystal austenite steel bulk material having an improved corrosion resistance, and its preparation process. The austenite steel bulk material comprises an aggregate of austenite nano-crystal grains containing 0.1 to 2.0% (by mass) of a solid solution type nitrogen, wherein an oxide, nitride, carbide or the like of a metal or semimetal exists as a crystal grain growth inhibitor between and/or in said nano-crystal grains. For preparation, fine powders of austenite steel-forming components, i.e., iron and chromium, nickel, manganese, carbon or the like are mixed with a substance that becomes a nitrogen source. Mechanical alloying (MA) is applied to the mixture, thereby preparing nano-crystal austenite steel powders having a high nitrogen concentration. Finally, the austenite steel powders are consolidated by sintering by means of spark plasma sintering, rolling or the like.

Abstract: The invention provides a high hard, strength and tough nano-crystal metal bulk material and a preparation process thereof. The metal bulk material comprises an aggregate of metal nano-crystal grains, wherein an oxide, nitride, carbide, boride or the like of a metal or semimetal exists as a crystal grain growth inhibitor between and/or in the nano-crystal grains. The respective fine powders of nano-metal bulk material-forming components are mechanically alloyed (MA), using a ball mill or the like, thereby preparing nano-metal powders. Then, hot forming-by-sintering treatment such as spark plasma sintering, extrusion and rolling or explosive forming is applied to the powders to obtain a high hard, strength and tough nano-crystal metal bulk material.

Abstract: A swimming pool utilizing deep-sea water to promote hygienic swimming and overall health. The pool is equipped with a deep-sea water collecting device which supplies the deep-sea water thereto and drainage equipment for maintaining a constantly fresh supply of deep-sea water in the pool. The pool may be equipped with a propulsion device such as a propeller, a large number of extensions on the bottom surface for avoiding sharks, facilities for fishing on its side, a means for generating fine air bubbles to be mixed into the deep-sea water, a solar power generation means, a wind power generation means and a deep-sea water desalination equipment. In addition, a pool using deep-sea water, accommodation facilities, dining facilities, facilities of a beauty shop/fitness gymnasium, fish breeding facilities and hydroponic facilities, which collect and use deep-sea water, are built on the beach.

Abstract: It is provided a swimming pool on the open sea effective for promoting health, and also surrounding facilities. The pool which floats on the sea is equipped with a deep-sea water collecting device which supplies the deep-sea water thereto. The pool may be equipped with a propulsion device such as a propeller, a large number of extensions on the bottom surface for avoiding sharks, facilities for fishing on its side, a means for generating fine air bubbles to be mixed into the deep-sea water, a solar power generation means, a wind power generation means and a deep-sea water desalination equipment. In addition, a pool using deep-sea water, accommodation facilities, dining facilities, facilities of a beauty shop/fitness gymnasium, fish breeding facilities and hydroponic facilities, which collect and use deep-sea water, are built on the beach.