Abstract:
The present invention is directed to ceramic articles containing processed carbon nanotubes (preferably graphene nanoribbons resulting from subjecting nanotubes to pressure and/or temperature) and to a method for making such articles including mixing ceramic material (preferably alumina M) and nanotubes, and processing the mixture so that nanotubes become transformed material T.
Abstract:
Die Erfindung betrifft ein Verfahren zum kontinuierlichen thermischen Entbindern eines durch Spritzgießen, Extrudieren oder Verpressen unter Verwendung einer thermoplastischen Masse hergestellten metallischen und/oder keramischen Formkörpers, enthaltend als Bindemittel mindestens ein Polyoxymethylenhomo- oder copolymerisat, in einem Entbinderungsofen umfassend die Schritte (a) Entbindern des Formkörpers in einem Entbinderungsofen bei einer Temperatur die 5 bis 20 °C, bevorzugt 10 bis 15 °C unterhalb der Temperatur einer zweiten Temperaturstufe liegt über einen Zeitraum von 4 bis 12 Stunden in einer ersten Temperaturstufe in sauerstoffhaltiger Atmosphäre, (b) Entbindern des Formkörpers bei einer Temperatur im Bereich von > 160 bis 200 °C über einen Zeitraum von 4 bis 12 h in sauerstoffhaltiger Atmosphäre in einer zweiten Temperaturstufe, und (c) Entbindern des Formkörpers bei einer Temperatur im Bereich von 200 bis 600 °C über einen Zeitraum von 2 bis 8 h in einer dritten Temperaturstufe, in sauerstoffhaltiger oder in neutraler oder reduzierender Atmosphäre, wobei der Formkörper während der Verfahrensschritte (a) und (b) durch den Entbinderungsofen transportiert wird.
Abstract:
L' invention a trait à un procédé d'élaboration d'une poudre comprenant du carbone, du silicium et du bore, le silicium se présentant sous forme de carbure de silicium et le bore se présentant sous forme de carbure de bore et/ou de bore libre comprenant les étapes suivantes : une étape de mise en contact d'un précurseur à base de carbone, d'un précurseur à base de silicium et d'un précurseur à base de bore BX 3 , X étant un atome d'halogène, de sorte à obtenir un mélange de ces trois précurseurs; une étape de soumission du mélange résultant à une pyrolyse laser, le précurseur à base de bore BX 3 étant chauffé, préalablement à l'étape de mise en contact et/ou simultanément à l'étape de mise en contact, à une température supérieure à la température de condensation dudit précurseur.
Abstract:
Ultrafine metal carbide or metal boride particles are consolidated by a method including sintering at intermediate pressures. A green body comprising the ultrafine metal carbide or metal boride particles may be preheated under vacuum and then pressurized to the intermediate sintering pressure. After sintering, the article may be densified at an intermediate temperature below the sintering temperature, and at an elevated pressure above the intermediate sintering temperature. The resultant consolidated metal carbide or metal boride article may then be cooled and used for such applications as armor panels, abrasion resistant nozzles, and the like.
Abstract:
The present invention concerns a method of producing an ultrahard abrasive composite material having a desirable overall thermal expansion coefficient mismatch, between the ultrahard particles and their matrix materials. The method includes the steps of providing a volume fraction of ultrahard particles having a pre-determined thermal expansion coefficient; determining the volume fraction and thermal expansion coefficient of a matrix material that would be required to produce an ultrahard composite material having a desired overall thermal expansion coefficient mismatch; contacting the ultrahard particles and the matrix material to form a reaction volume; and consolidating and sintering the reaction volume at a pressure and a temperature at which the ultrahard particles are crystallographically or thermodynamically stable. Ultrahard composites where the ultrahard particles are cubic boron nitride and/or diamond are provided, with matrix materials chosen to produce thermal expansion mismatches within specific value ranges, and associated, controlled residual stresses. Ultrahard composite matrices involving combinations of nitride matrices such as titanium nitride/tantalum nitride, and titanium nitride/ chromium nitride are exemplified.
Abstract:
This invention is directed to novel and useful process for the preparation of boron carbide, boron nitride and silicon carbide comprising carbidization or nitrization step of boron oxides or silicon oxides, using nanoparticles substrates.
Abstract:
A method is provided for synthesizing beads using starting ceramic, metal, or mineral powders. Typical size of these round beads can range from about 0.1 mm to about 10 mm based on the processing variables. In the method, a slip is obtained which contains a metal, ceramic, and/or mineral powder dispersed in a solvent and an organic binder, such as a grain flour. Droplets of the slip are contacted with heated oil for a sufficient time to form beads. The beads are separated from the oil and dried to remove entrained water. The beads are fired at a temperature sufficient to produce beads possessing desired physical or chemical characteristics. The beads have useful biomedical applications as bone filler materials for bone fixation and bone growth. The beads may be coated with chemical catalyst agents and function as catalyst supports in chemical processes.