Abstract:
A method for increasing the resolution when forming a three-dimensional article through successive fusion of parts of a powder bed, said method comprising providing a vacuum chamber, providing an electron gun, providing a first powder layer on a work table inside said vacuum chamber, directing an electron beam from said electron gun over said work table causing the powder layer to fuse in selected locations to form a first cross section of said three-dimensional article, providing a second powder layer on said work table, directing the electron beam over said work table causing said second powder layer to fuse in selected locations to form a second cross section of said three-dimensional article, reducing the pressure in the vacuum chamber from a first pressure level to a second pressure level between the providing of said first powder layer and said second powder layer.
Abstract:
The present invention relates to a process for carburizing a metal article comprising: (1) heating the metal article to an elevated temperature, (2) coating the heated metal article with a graphite suspension to produce a graphite coated metal article, wherein the graphite suspension is comprised of graphite and an organic or inorganic liquid having a boiling point of at least 50° F. (28° C.) less than the elevated temperature to which the metal article is heated, (3) heat treating the graphite coated metal article under a non-oxidizing environment at a temperature which is sufficient to promote the diffusion of carbon into the metal structure of the article to produce a carburized metal article, and (4) cooling the carburized metal article to ambient temperature.
Abstract:
Hydrophobic metal nanoparticles are prepared by reducing a metal precursor in a non-polar or low polar organic solvent with or without volume expansion by adding CO2.
Abstract:
In order to achieve the object of providing a mixture by means of which, in particular, sintered moldings can be obtained that are virtually free of surface stains produced by soot particles, a mixture is proposed which comprises at least one pressing aid and at least one additive, wherein the additive is selected from a group of substances which have releasable carbon dioxide.
Abstract:
The invention relates to a method of preparing a particle-based composition, comprising: (i) bringing into contact a mixture comprising a dendritic structure and a metal compound precursor in a fluid, under temperature and pressure conditions such that the mixture is not soluble in the fluid; and (ii) chemically converting the metal compound precursor.
Abstract:
The process for producing, processing, sintering, pressing or extruding thermoelectric materials with heat treatment under inert gas or under reduced pressure at temperatures in the range from 100 to 900° C. comprises producing, processing, sintering, pressing or extruding in the presence of oxygen scavengers which form thermodynamically stable oxides in the presence of free oxygen under the production, processing, sintering, pressing or extrusion conditions and hence keep free oxygen away from the thermoelectric material.
Abstract:
A method and a device are described for the production of metal powder or alloy powder of a moderate grain sizes less than 10 μm, comprising or containing at least one of the reactive metals zirconium, titanium, or hafnium, by metallothermic reduction of oxides or halogenides of the cited reactive metals with the aid of a reducing metal, wherein said metal powder or alloy powder is phlegmatized by adding a passivating gas or gas mixture during and/or after the reduction of the oxides or halogenides and/or is phlegmatized by adding a passivating solid before the reduction of the oxides or halogenides, wherein both said reduction and also said phlegmatization are performed in a single gas-tight reaction vessel which can be evacuated.
Abstract:
An improved method of reducing a mixed metal oxide composition comprising oxides of nickel, cobalt, copper and iron in a hydrogen atmosphere to produce a mixture of the respective metals, the improvement wherein the atmosphere further comprises water vapour at a concentration, temperature and time to effect selective reduction of the oxides of nickel cobalt and copper relative to the iron oxide to produce the metallic mixture having a reduced ratio of metallic iron relative to metallic nickel, cobalt and copper.
Abstract:
The invention relates to a method of preparing a particle-based composition, comprising: (i) bringing into contact a mixture comprising a dendritic structure and a metal compound precursor in a fluid, under temperature and pressure conditions such that the mixture is not soluble in the fluid; and (ii) chemically converting the metal compound precursor.
Abstract:
A ferromagnetic metal powder for a magnetic recording medium that combines good magnetic properties and oxidation stability, and a magnetic recording medium using the powder. A method of producing the magnetic powder comprises using oxygen to form an oxide film, then changing the state of the oxide film by using moderate gas phase activation treatment in an active gas, using, for example, CO or H2 or other such gas having reducing properties. ESCA-based measurements show that the binding energy peak of the powder is more to the low energy side compared to when the above treatment is not used, showing that the oxide film has oxidation resistance. The storage stability of a magnetic recording medium is improved by using the powder.