Abstract:
Matériau céramique composite particulaire, comprenant : des particules en au moins une première céramique ultraréfractaire « UHTC », la surface externe de ces particules étant recouverte au moins en partie par une couche poreuse en au moins une deuxième céramique ultraréfractaire sous forme amorphe; et les particules définissant entre elles un espace; éventuellement, des amas poreux de ladite au moins une deuxième céramique ultraréfractaire sous forme amorphe, répartis dans ledit espace; une matrice dense en au moins une troisième céramique ultraréfractaire sous forme cristallisée remplissant au moins en partie ledit espace; éventuellement, un revêtement dense en au moins ladite troisième céramique ultraréfractaire sous forme cristallisée, recouvrant la surface externe de ladite matrice, ladite matrice et ledit revêtement représentant de 5% à 90% en masse par rapport à la masse totale du matériau. Pièce comprenant ledit matériau céramique composite particulaire. Procédé de fabrication de ladite pièce.
Abstract:
It is disclosed a method for manufacturing a ceramic object, the method comprising the following steps: providing a sample of the object by means of a three-dimensional printing technology, wherein the sample is made from a precursor material comprising a material comprising carbon, and an inorganic component; and submitting the sample to a thermal treatment comprising a process involving the reaction of the carbon with the inorganic component in order to obtain the ceramic object.
Abstract:
L'invention concerne notamment un procédé d'imprégnation d'une texture fibreuse de forme creuse, le procédé comprenant au moins les étapes suivantes : - introduire une première suspension (10) comprenant une première poudre de particules solides en matériau céramique ou en carbone dans un volume intérieur (2) délimité par une face interne (la) d'une texture fibreuse (1) de forme creuse placée dans un moule, une face externe (lb) de la texture fibreuse (1) étant présente en regard d'une paroi (3) du moule, et - imprégner par action de la force centrifuge la texture fibreuse (1) par la première suspension (10) par mise en rotation du moule sur lui-même en faisant varier la vitesse de rotation du moule durant l'imprégnation de la texture (1) par la première suspension (10).
Abstract:
A ceramic matrix composite includes a plurality of fibers embedded in a matrix. The composition of the matrix is selected to achieve a desired relationship between the mechanical and thermal properties of the matrix and the fibers. A method for producing a ceramic matrix composite, comprising the steps of: forming a network of fibers; and depositing a matrix material having a first component and a second component on the network of fibers, wherein one of the first and second components is deposited in an amount greater than its stoichiometric amount in relation to the other component. A ceramic matrix composite, comprising: a matrix having a creep rate at a specified temperature, the matrix including a first component and a second component, wherein one of the first and second components is present in an amount greater than its stoichiometric amount in relation to the other component; and a plurality of fibers embedded in the matrix, the fibers having a lower or the same creep rate at the specified temperature than the creep rate of the matrix. Preferably the matrix material is SiC, which means that either there is more Si or there is more C. The ceramic fibers contain preferably an interface coating of silicon doped BN. The matrix material is preferably made by CVI.
Abstract:
A method of densifying a CMC article includes the steps of pyrolyzing a CMC article until a desired initial porosity is achieved, coating CMC pores within the CMC article with carbon, pyrolyzing the carbon to form carbon pores, coating the carbon pores with silicon, and heat treating the CMC article to create a silicon carbide filled pore integrated with silicon carbide of the CMC article to densify the CMC article.
Abstract:
A fiber having an environmental barrier coating is provided that includes, in one illustrative form, a Hi Nicalon preform assembled in a tooling for chemical vapor infiltration and cleaned to remove sizing char from fibers of the Hi Nicalon preform; a ytterbium doped silicon carbide coat located over the Hi Nicalon preform; a boron nitride interface coat applied over the ytterbium doped silicon carbide coat; and a silicon carbide coat applied over the boron nitride interface coat. In another embodiment the fiber has an environmental barrier coating, comprising: a Hi Nicalon S fiber; wherein the Hi Nicalon S fiber is coated in tow form with yttrium doped silicon carbide; and a silicon doped boron nitride coat applied over the yttrium doped silicon carbide. In a third embodiment the fiber has an environmental barrier coating, comprising: a T-300 carbon fiber preform assembled in tooling for chemical vapor infiltration; alternating layers of silicon carbide and boron carbide are applied over the preform; and a silicon doped boron nitride interface coat applied over the silicon carbide coat.
Abstract:
Method for manufacturing a β-SiC shaped piece comprising mesopores with a diameter of between 6 nm and 100 nm representing a mesopore volume (determined by mercury intrusion porosimetry) greater 0.35 cm 3 /g, said method comprising the transformation of a mesoporous carbon preform with at least one silicon source into silicon carbide (β-SiC), said silicon source being able to be incorporated in said preform or contributed from outside, said carbon preform having mesopores with a diameter of between 6 nm and 100 nm with a mesopore volume greater than 0.35 cm 3 per gram of carbon. This β-SiC mesoporous shaped piece can be used as a catalyst carrier for chemical reactions involving a liquid phase, and in particular for the Fischer-Tropsch reaction.
Abstract:
Methods and materials for forming in-situ features in a CMC component (200) are described. The method of forming a ceramic matrix composite component with cooling features, comprises forming a preform tape (120), laying up (122) said preform tape to a desired shape, placing a high-temperature resistant fugitive material insert (30) of preselected geometry in the preform tape of the desired shape, compacting (134) the preform tape of the desired shape, burning out (138) the preform tape of the desired shape, melt infiltrating (140) the desired shape, removing the high-temperature resistant insert to form the cooling features during one of the burning out or the melt infiltrating or following the burning out or the melt infiltrating.
Abstract:
Die vorliegende Erfindung betrifft ein Verfahren zur Herstellung eines Keramikkörpers, der aus zwei monolithisch miteinander verbundenen Zonen, die sich hinsichtlich ihrer Porenstruktur unterscheiden, aufgebaut ist. Das erfindungsgemäße Verfahren beruht insbesondere auf der Kombination von Gefriergießen (Freeze Casting) und Schlickergußverfahren.
Abstract:
The present invention includes high temperature-stable combustion aids with ceramic plates 1 and hollow profiles 4 having webs 2 and 5. The invention further includes a shelf system 7 comprising at least two hollow profiles 4 with at least two webs 5 on one side of the hollow profile 4 and at least one ceramic plate 1 that is arranged on the hollow profiles 4, wherein the hollow profile 4 and the ceramic plate 1 contact one another only in the area of the webs 2, 5. The contact surface of the hollow profiles 4 and the ceramic plates 1 is reduced to a point contact by a mutually inclined paths of the webs 2 and 5 relative to one another.