摘要:
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.
摘要:
Process for direct nitriding of metals of relatively low melting point with the aid of a nitrogen-containing gas, in which a powder of at least one of the metals is mixed with a refractory powder, the mixture is heated under an atmosphere of nitrogen-containing gas at atmospheric pressure until the start of a rapid and exothermic nitriding reaction, and this reaction, which proceeds at a temperature generally higher than that of the melting point of the metals without apparent melting being observed, is allowed to proceed until all of the metals have been consumed, in order to obtain a highly porous solid mass which is easy to grind and is based on metal nitrides or metal oxynitrides.
摘要:
Elements for use as protecting fuel contacting surfaces of a gas turbine engine are protected from carbon deposition by heating the element in a nitrogen containing atmosphere for sufficient time to cause penetration and absorption of nitrogen into the grain boundaries of the alloy surface, which acts as a barrier between the hydrocarbon fuel and the catalytic elements in the surfaces.
摘要:
A method of treating apertured plates with a gaseous medium, e.g. to produce a nitride surface layer thereon, by placing the plates in rows in a furnace and causing the gaseous medium to flow across the surfaces of the plates by circulating the medium through the furnace and deflecting the medium as it flows along the furnace walls away from the walls to give a substantially uniform flow of gas across the plate surfaces.
摘要:
A method of nitriding an article of refractory-nitride-forming metal or metalloids. A consolidated metal or metalloid article is placed inside a microwave oven and nitrogen containing gas is introduced into the microwave oven. The metal or metalloid article is heated to a temperature sufficient to react the metal or metalloid with the nitrogen by applying a microwave energy within the microwave oven. The metal or metalloid article is maintained at that temperature for a period of time sufficient to convert the article of metal or metalloid to an article of refractory nitride. in addition, a method of applying a coating, such as a coating of an oxide, a carbide, or a carbo-nitride, to an article of metal or metalloid by microwave heating.
摘要:
A rapid thermochemical treatment automatic installation for a charge constituted by parts, intended particularly for the mechanical industry, which includes a plurality of treatment modules such as an induction preheating module, thermochemical treatment modules, a quenching module, a device for carrying out the loading and unloading of the parts stacked in columns and a transfer device of the columns of parts between the various treatment modules. The installation includes a fixed circular plate on the periphery of which are distributed various treatment modules, which are suspended beneath the lower surface of the plate, which plate is formed with openings which can be tightly closed for the introduction of the parts to be treated in the respective modules, and a mobile disc rotably and coaxially mounted above the fixed plate, the mobile disc receiving the transfer device so that the transfer device can be brought successively above the loading/unloading station and the access station to the various modules for respectively introducing in the installation a column of parts to be treated, transferring the column of parts to be treated, transferring the column successively to the various modules and extracting from the installation the column of parts after treatment.
摘要:
The present invention relates to powder particles consisting of hard principles and binder metal for the manufacture of superior, uniquely fine-grained hard material alloys and to a procedure for the preparation of said particles.The preparation is performed in an economical way because the procedure starts from conventional melt metallurgical raw materials. A pre-alloy consisting of hard principle forming and binder phase forming elements is subjected to a heat treatment such as nitriding and carburizing after being crushed. The final product is particles composed by hard principle phases and binder metal phases formed "in situ" in an effective binding.
摘要:
The quality of superconducting cavity resonators depends to a very great extent on the surface quality of the cavities. The invention relates to a process for the manufacture of superconducting cavity resonators with improved surface quality, whereby even complex shaped cavity resonators can be made with cavities coated with NbN.
摘要:
A method and apparatus for forming a layer of a carbide or nitride of, for example, titanium or vanadium on the surface of material to be treated in a fluidized bed furnace. A refractory powder for forming a fluidized bed, a vessel or vessels filed with powder of a treating agent, and the material to be treated are placed in the furnace. The treating agent includes powder of at least one carbide or nitride forming metal or alloy and powder of at least one compound selected from the group consisting of chlorides, fluorides, bromides, iodides and boro-fluorides of alkali and alkaline earth metals and/or at least one of an ammonium halide and a metal halide. A fluidizing gas is introduced into the furnace under heat to form a fluidized bed in which the surface of the material to be treated is treated. The vessel or vessels are placed in the furnace in a spaced-apart relation from the material to be treated, so that no powder of the treating agent may adhere to the surface of the material to be treated.
摘要:
An improved fabrication process for cobalt-enriched cemented carbide substrates is disclosed, in which an article is generally comprised of tungsten carbide, cobalt, and carbides, nitrides or carbonitrides of titanium, tantalum, and niobium, or mixtures thereof. In one aspect of the invention the article is contacted with nitrogen gas and then sintered in the absence of nitrogen gas to form a cobalt-enriched, B-1 phase-depleted zone. The article is then sintered in nitrogen gas to form a B-1 phase enriched layer on the surface of the article. Additionally, a metal oxide wear layer can be provided on the article.