Abstract: A motor rotary shaft according to the present invention is constructed only at the surface layer of a journal portion with a hard nitride layer, so that the resultant motor rotary shaft is available at a low cost, not so heavy and excellent in durability in comparison with a case employing a hard material for the whole motor rotary shaft. Also, a method of manufacturing a motor rotary shaft according to the present invention employs fluorinating process prior to nitriding process to change a passive coat layer such as oxide layer on the surface of the journal portion to a fluoride layer, which protects the same surface. Therefore, even when there is space of time between formation of fluoride on the surface of the journal portion and nitriding process, the fluoride layer protects and keeps the surface of the journal portion in a favorable condition, resulting in that re-formation of oxide layer on that surface is prevented.

Abstract: A crank shaft is constructed only at the surface layer of a journal portion with a hard nitride layer, so that the resultant crank shaft is available at a low cost, not so heavy and excellent in durability in comparison with a case employing a hard material for the whole crank shaft. Also, a method of manufacturing a crank shaft according to the present invention employs fluorinating process prior to nitriding process to change a passive coat layer, such as oxide layer on the surface of the journal portion to a fluoride layer, which protects the same surface. Therefore, even when there is space of time between formation of fluoride on the surface of the journal portion and nitriding process, the fluoride layer protects and keeps the surface of the journal portion in a favorable condition, resulting in that re-formation of oxide layer on that surface is prevented.

Abstract: The invention is composed of a non-aluminium metallic foil with a ceramic particle dotted layer formed on one side thereof is used and the non-aluminium metallic foil is wound on the peripheral surface of an inner shell of a duplex shell body in a state that the ceramic particle dotted layer is faced inwardly, wherein the circumference of the multi-layeredly wound layer is covered with an outer shell of the duplex shell body, and a space between the inner shell and the outer shell is sealed and evacuated.

Abstract: The present invention relates to nickel alloy products with their surfaces nitrided and hardened which are formed by pressure casting nickel alloy material, and nitrided and hardened layers are formed in surface layers. Since the nitrided and hardened surfaces of the nickel alloy products according to the invention have much better corrosion resistance than iron products have, anticorrosion treatment such as plating is not required, and rich lubricity and excellent tightening property can be obtained without having seizure and scuffing phenomena.

Abstract: The invention is composed of a non-aluminium metallic foil with a ceramic particle dotted layer formed on one side thereof, the non-aluminium metallic foil is wound on the peripheral surface of an inner shell of a duplex shell body in a state that the ceramic particle dotted layer is faced inwardly; the circumference of the multi-layeredly wound layer is covered with an outer shell of the duplex shell body, and a space between the inner shell and the outer shell is sealed and evacuated.

Abstract: This invention allows to form a nitrided hard layer on the surface of an austenitic stainless steel screw by forming a nitrided layer thereon and to prevent causing rust on some parts such as a screw head portion which is in contact with the outside air by removing the nitrided hard layer to expose austenitic stainless steel base which has sufficient corrosion resistance. On the contrary, in a thread part and the like of the screw, the nitrided hard layer is left and to thereby improves hardness and the like to strengthen tapping functions and the like of the screw. In the method for manufacturing the austenitic stainless steel screw according to the invention, the austenitic stainless steel screw is held in a fluorine- or fluoride-containing gas atmosphere prior to nitriding to form a fluorided film on its surface and then is nitrided in that state. Accordingly, so formed nitrided hard layer becomes uniform and deep to obtain an austenitic stainless steel screw having excellent surface properties.

Abstract: The present invention relates to nickel alloy products with their surfaces nitrided and hardened which are formed by pressure casting nickel alloy material, and nitrided and hardened layers are formed in surface layers. Since the nitrided and hardened surfaces of the nickel alloy products according to the invention have much better corrosion resistance than iron products have, anticorrosion treatment such as plating is not required, and rich lubricity and excellent tightening property can be obtained without having seizure and scuffing phenomena.

Abstract: A crank shaft is constructed only at the surface layer of a journal portion with a hard nitride layer, so that the resultant crank shaft is available at a low cost, not so heavy and excellent in durability in comparison with a case employing a hard material for the whole crank shaft. Also, a method of manufacturing a crank shaft according to the present invention employs fluorinating process prior to nitriding process to change a passive coat layer, such as oxide layer on the surface of the journal portion to a fluoride layer, which protects the same surface. Therefore, even when there is space of time between formation of fluoride on the surface of the journal portion and nitriding process, the fluoride layer protects and keeps the surface of the journal portion in a favorable condition, resulting in that re-formation of oxide layer on that surface is prevented.

Abstract: This invention allows the surface of an austenitic stainless steel screw surface to be formed into a hard nitrided layer so as to harden and a part such as a screw head which is in contact with outside air is removed its own ultra hard surface layer in the hard nitrided layer by scouring or the like to be rust preventive. Even if the ultra hard surface layer is thus removed, an inner hard layer in the hard nitrided layer is present beneath the surface layer to be able to maintain a hard state of the screw surface. In the method for manufacturing the austenitic stainless steel screw according to the invention, upon forming said hard nitrided layer on the screw surface by nitriding, the austenitic stainless steel screw surface is cleaned with a fluorine- or fluoride-containing gas prior to nitriding.

Abstract: The surface layer of a hard austenitic stainless steel screw is formed as nitrided layer and then is covered by a plating coat or a resin coat to give properties such as shortening the boring time as well as heightening the surface hardness of the screw itself.

Abstract: Nitrided stainless steel products having a base material of stainless steel containing austenitic stainless steel. At least a portion of the surface layer of the base material is composed of a nitrided hard layer in accordance with the following conditions (A) and (B):(A) the nitrided hard layer substantially does not contain crystalline chromium nitride, and(B) the nitrided hard layer contains from 2 to 12% by weight N atoms.

Abstract: In accordance with this invention, a waste gas containing toxic NF.sub.3 gas is contacted with a honeycomb structure of a carbonaceous material to thereby convert NF.sub.3 into nontoxic CF.sub.4 and N.sub.2 gases with high efficiency.

Abstract: This invention relates to an apparatus wherein a vacuum chamber is divided into two spaces, the substrate heating space and the crystal growth space, so that the degree of vacuum in the substrate heating space is set lower than the pressure for the Si growth and the degree of vacuum in the crystal space is set corresponding to the pressure for Si growth to thereby grow Si based semiconductor with excellent reproducibility over a long period. Moreover, heat efficiency toward the substrate is heightened by enclosing the upside and the circumference of the heating means with the heat shielding body to cut energy cost.

Abstract: Upon forming a plating coat on steel works, the works are held in a fluorine- or fluoride-containing gas atmosphere in a heated condition to thereby remove oxidized scales such as SiOx, MnOx and the like on the surface layer of the work and to form a fluoride layer to prevent forming new oxidized scale. The fluoride layer is easily eliminated by an action of added flux to a plating bath or by heating the fluorinated steel works in an atmosphere containing hydrogen prior to dipping in the plating bath to activate the steel surface. The activated steel surface is improved in compatibility with the plating bath and the like to realize a good quality plating coat formation.

Abstract: This invention allows the surface of an austenitic stainless steel screw surface to be formed into a hard nitrided layer so as to harden and a part such as a screw head which is in contact with outside air is removed its own ultra hard surface layer in the hard nitrided layer by scouring or the like to be rust preventive. Even if the ultra hard surface layer is thus removed, an inner hard layer in the hard nitrided layer is present beneath the surface layer to be able to maintain a hard state of the screw surface. In the method for manufacturing the austenitic stainless steel screw according to the invention, upon forming said hard nitrided layer on the screw surface by nitriding, the austenitic stainless steel screw surface is cleaned with a fluorine- or fluoride-containing gas prior to nitriding.

Abstract: A hard nitrided layer is formed on austenitic stainless steel by holding the austenitic stainless steel in a heated condition under a fluorine- or fluoride-containing atmosphere and then nitriding it so that a close uniform nitriding layer can be formed, resulting the remarkable improvement in the surface hardness of the above-mentioned austenitic stainless steel. The temperature in the above-mentioned nitriding treatment is set below 450.degree. C. so that high anti-corrosion property, originally inherent in austenitic stainless steel, can be retained without deterioration.

Abstract: An austenitic stainless steel screw having a nitride hard layer on its surface to prevent corrosion on parts of the screw such as a screw head which is in contact with the environment by removing a portion of the nitride hard layer to expose austenitic stainless steel base. By contrast, in the thread part and the like of the screw, the nitride hard layer is retained to improve the hardness and the tapping functions of the screw. In the method for manufacturing, the austenitic stainless steel screw is exposed to a fluorine-or fluoride-containing gas atmosphere prior to nitriding to form a fluoride film on its surface and then is nitrided in that state. Accordingly, the so formed nitride hard layer becomes uniform and deep to obtain an austenitic stainless steel screw having excellent surface properties.

Abstract: A method and an apparatus for separating a specific component gas from a mixed gas, wherein granular adsorbent is held in a sealed space in a layered state, easily adsorptive gas is adsorbed to the granular adsorbent by blowing material mixed gas into the adsorbent layers and contacting the granular adsorbent with a counter-current of material gas, and the granular adsorbent is transferred gradually out of the sealed space, and reactivated by desorbing the easily adsorptive gas from the granular adsorbent, and the reactivated granular adsorbent is returned to the inside of the sealed space to be reused. Therefore, frequent actions of opening and closing valves are unnecessary, so that it is possible to separate and produce excellent product gas with high purity.

Abstract: Stainless steel foil 31 is wound spirally on the circumference of a pipe body 30 from one end to another end of the pipe body 30 to overlap itself and the periphery of the pipe body 30 is covered with the overlapped layer to give a heat insulation pipe body. The stainless steel foil 31 is wound on the circumference of the pipe body 30 from one end thereof, while ceramic particles 32 are flame sprayed to the wound part of the stainless steel foil 31 to form a ceramic particle dotted layer 33. Then on the periphery of the stainless steel foil 31 with the ceramic particle dotted layer 33 formed, a part of the stainless steel foil subsequent to one end of said stainless steel foil is wound shiftedly toward an axis direction and at the same time the newly wound stainless steel foil part is flame sprayed with ceramic particles 32 to form a ceramic particle dotted layer 33 and these steps are repeated.

Abstract: This invention relates to a method for forming a uniform, deep nitride layer on and in steel works at low cost, wherein a steel work is fluorided in heated condition in an atmosphere of a mixed gas composed of fluorine gas and inert gas and, then, nitrided in heated condition in an atmosphere of nitriding gas.