Abstract: A method of nitriding nickel alloy comprising steps of holding nickel alloy in an atmosphere of fluorine- or fluoride-containing gas in a heated condition and holding the fluorinated nickel alloy in a nitriding atmosphere in a heated condition to provide the nickel alloy with improved surface hardness by forming a deep uniform nitrided layer on the surface of the nickel alloy.

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: In this invention, a method of manufacturing a colored metallic sheet comprises steps of holding a surface to be painted of metallic plates 10 in a fluorine- or fluoride-containing atmosphere in a heated condition to form a fluorided layer on the surface to be painted, removing the formed fluorided layer on the surface just before painting the surface to expose a metallic base, and painting the exposed metallic base surface.

Abstract: A process for manufacturing rolled articles of titanium material comprising steps of contacting heated titanium material with fluorine- or fluoride-containing gas to form a fluoride layer on the surface of the titanium material, removing the fluoride layer formed thereon just before rolling and then rolling the titanium material to give a rolled article. With this structure, passive coat layers, such as the oxide layer on the surface of the titanium material is changed to a fluoride layer. The fluoride layer protects the surface of the titanium material. Therefore even if there is space of time between formation and removal of the fluoride layer, the fluoride layer formed on the surface of the titanium material protects the same surface in a favorable condition, which results in preventing re-formation of an oxide layer on the titanium material surface.

Abstract: This invention relates to a method of nitriding steel material in a second heat treatment furnace after fluorinating the steel material in a first heat treat furnaceto form a deep and uniform nitrided layer. Then, steel material is treated smoothly by defining the ratio of establishing said both furnaces for fluorinating and niriding on the basis of treating time required for said both treatments since time required for each treatment is different.

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 H.sub.2 gases with high efficiency.

Abstract: Steel is nitrided first by treating the steel to be nitrided with NF.sub.3 at elevated temperatures to form a fluorinated layer on the steel, and then the steel is nitrided by heating in a nitriding atmosphere.

Abstract: A reactant gas is fed to a dispersing chamber which is disposed under a reaction chamber, and both disposed within a vacuum chamber. The reactant gas is dispersed and then fed through a plurality of communicating holes to the reaction chamber. A second reactant gas is fed to a lower dispersing chamber. After dispersion, this second gas is fed through pipes through the first dispersing chamber and into the reaction chamber around the first reaction gas. Said first reactant gas is blown off downward from the end opening of the feeding pipe and dispersed in parallel along the collar portion and dispersed homogeneously in the first reactant gas dispersing chamber, and in the state, is introduced to the reaction chamber via communicating holes.

Abstract: This invention relates to a method of nitriding steel material in a second heat treatment furnace after fluorinating the steel material in a first heat treat furnace to form a deep and uniform nitrided layer. Then, steel material is treated smoothly by defining the ratio of establishing said both furnaces for fluorinating and nitriding on the basis of treating time required for said both treatments since time required for each treatment is different.

Abstract: Steel is nitrided first by treating the steel to be nitrided with NF.sub.3 at elevated temperature to form a fluorinated layer on the steel, and then the steel is nitrided by heating in a nitriding atmosphere.

Abstract: The present invention relates to an apparatus for producing semiconductors utilizing vacuum chemical epitaxy (VCE) method.Said VCE method has a high utilization efficiency of reactant gas and can finish the surface of a semiconductor layer formed on the surface of a substrate smoothly in comparision with a conventional Metalorganic Chemical Vapor Deposition Method(MOCVD). However, in case of forming semiconductor layer on the surface of a substrate with a large area, it is impossible to form homogeneous semiconductor layer.According to the present invention, a reactant gas dispersing chamber is disposed under a reaction chamber disposed within a vacuum chamber, the both chambers are communicated by a plurality of communicating holes, a feeding pipe for supplying reactant gas is extended into the reactant gas dispersing chamber, an end opening thereof is faced downward and a color portion is formed in parallel at the circumference of the end opening.

Abstract: The primary object of the invention is to clean and activate the surface of metallic works prior to such thermal treatment as nitriding, thermal spraying or dip plating by removing oxidized and other passive layers and foreign matters from the metallic work surface.The method of pretreating metallic works comprises heating a metallic work in a furnace and introducing a fluorine- or fluoride-containing gas into the furnace in that state to thereby cause destruction and elimination of the foreign matters adhering to the metallic work surface and of the oxidized layer occurring on the metallic work surface and simultaneous formation of a fluorinated layer. Just prior to the main thermal treatment, for example nitriding, the fluorinated layer is decomposed and eliminated by introducing an appropriate gas, for example H.sub.2, into the furnace. In this way, the metallic work reveals its cleaned and activated surface.

Abstract: Apparatus for continuously producing semiconductor films on substrates in a vacuum chamber. A plurality of reaction chambers are provided within the vacuum chamber, substrates are supported by a top plate and transferred to each reaction chamber, which are filled with a certain reactant gas mixture while the substrates are heated from above the reaction chamber. Continuous treatment of the substrates is provided with an increase in reactant gas utilization efficiency. Disturbance of reactant gas flow by thermal convection is prevented and semiconductor layers having smooth surfaces are formed.

Abstract: There is provided an apparatus for manufacturing nitrogen gas and oxygen gas of very high purity by cryogenic liquefaction, and without using an expansion turbine. Supercooled and compressed air is sent to a distilling tower where it is mixed with and cooled by the latent heat of vaporization of liquid nitrogen from any external source. Utilizing the difference between their boiling points, nitrogen is taken out as gas while oxygen remains as liquid. The oxygen is concentrated in an oxygen condenser and then further concentrated in an oxygen distilling tower mixed with liquid oxygen from an external source as the refrigerant.

Abstract: The apparatus comprises an oxygen gas production apparatus comprising an air compression means for compressing air from an outside source, a purification means for removing carbon dioxide gas and water vapor from the air compressed by said air compression means, a heat exchange means for chilling the compressed air from said purification means to a cryogenic temperature, a fractionation column for liquefying and fractionating the compressed air chilled to a cryogenic temperature by said heat exchange means and holding nitrogen in gaseous state and oxygen in liquid state, a liquid oxygen storage means for receiving liquid oxygen from an outside source and storing the same, a line for introducing into said fractionation column the liquid oxygen from said liquid oxygen storage means as the refrigerant for liquefaction of compressed air, a liquid level detection-control means for monitoring the liquid level of oxygen held in said fractionation column and controlling the amount of feed of liquid oxygen from said l

Abstract: The invention provides an apparatus for production of highly pure oxygen gas by cryogenic liquefaction and separation of air which does not include an expansion turbine which is known to frequently cause operation troubles.

Abstract: There is disclosed a high-purity nitrogen gas production equipment for production of ultra-high-purity nitrogen gas for use in the electronics and other industries, for example in connection with the production of silicon semiconductors. The conventional nitrogen gas production equipment of cryogenic air separation type tends to develop troubles and yields product nitrogen gas only at high cost and in comparatively low purity.

Abstract: A producing apparatus of highly pure nitrogen gas which is used in electronic industry for manufacturing silicon semiconductors.Conventional nitrogen gas producing apparatus of low temperature separation method and of PSA method are subjected to troubles frequently, the cost of the obtained product nitrogen gas is high, yet the purity is not very high.By the apparatus of this invention, the liquefied nitrogen storage means (15) is connected to the heat exchangers (13, 14) through the inlet channel (16), the compressed air reaching the heat exchangers (13, 14) through the air compressor (9) and the impurity removing means (12) is cooled down to ultra low temperature by using the evaporation heat of the liquefied nitrogen then is sent into the rectifying column (15), and the nitrogen is taken out in gas form by utilizing the difference in the boiling point and oxygen is left in liquid form.

Abstract: There is disclosed high-purity nitrogen gas production equipment for production of ultra-high-purity nitrogen gas for use in the electronics and other industries, for example in connection with the production of silicon semiconductors. The conventional nitrogen gas production equipment of cryogenic air separation type tends to develop troubles and yields product nitrogen gas only at high cost and in comparatively low purity. The equipment according to the invention is such that a liquid nitrogen storage means (23) is connected via a first feeding pipeline (24a) to a distillation column (15) into which air is introduced from the outside via an air compression means (9) and heat exchange means (13), (14) while the above storage means (23) is also connected via a second feeding line (24b) to the above heat exchange means (13), (14).

Abstract: A producing apparatus of highly pure nitrogen gas which is used in electronic industry for manufacturing silicon semi-conductors. Conventional nitrogen gas producing apparatus of low temperature separation method and of PSA method are subjected to troubles frequently, the cost of the obtained product nitrogen gas is high, yet the purity is not very high. By the apparatus of this invention, the liquefied nitrogen storage means (23) is connected to rectifying column (15) through the inlet channel (24), the ultra low temperature compressed air supplied into the rectifying column (15) through the air compression means (9), removing means (12) and heat exchangers (13) (14) is cooled further by the evaporating heat of the liquefied nitrogen, the nitrogen is taken out in gas form by utilizing the difference in boiling point, and oxygen is left as liquid. The obtained nitrogen gas is combined with the gassified liquid nitrogen from the liquefied nitrogen storage means (23) and made into product nitrogen gas.