An inorganic fibrous shaped refractory article having a high bio-solubility which is capable of exhibiting a desired heat resistance without containing expensive ceramic fibers, alumina powder and silica powder can be provided at a low production cost and with a low product price.

An inorganic fibrous shaped refractory article includes 2 to 95 mass% of rock wool, 2 to 95 mass% of inorganic powder having a needle-like crystal structure and 3 to 32 mass% of a binder. Preferably, in the an inorganic fibrous shaped refractory article, the inorganic powder having a needle-like crystal structure has an average length of 1 to 3000 µm and an aspect ratio of 1 to 1000, and more preferably the inorganic powder having a needle-like crystal structure is wollostonite powder or sepiolite powder.

A honeycomb structure of the present invention includes a honeycomb unit having a plurality of through holes defined by partition walls along a longitudinal direction of the honeycomb unit, wherein the honeycomb unit is manufactured by molding raw material paste by extrusion molding and thereafter firing the molded raw material paste, the raw material paste containing zeolite ion-exchanged with iron ions and an inorganic binder, and the specific surface area of the zeolite is more than or equal to 500 m²/g and less than or equal to 800 m²/g, and the external surface area of the zeolite is more than or equal to 40 m²/g and less than or equal to 80 m²/g.

An object of the present invention is to provide a honeycomb structured body which can prevent the damage to the honeycomb structured body caused by the force applied to a radial direction and also has a low heat capacity, and the honeycomb structured body comprises a plurality of pillar-shaped honeycomb fired bodies combined with one another by interposing an adhesive layer therebetween, each of the honeycomb fired bodies having a large number of through holes, which are longitudinally formed in parallel with one another and divided by a partition wall, wherein

the honeycomb fired bodies comprise inorganic particles and an inorganic binder,

the honeycomb fired bodies include a center-portion honeycomb fired body located in a center portion and a peripheral-portion honeycomb fired body located in a peripheral portion in a cross section perpendicular to the longitudinal direction,

the center-portion honeycomb fired body has a square cross-sectional shape perpendicular to the longitudinal direction of the honeycomb structured body,

the center-portion honeycomb fired body has an area of 2500 to 5000 mm² in the cross-section,

a cross-sectional shape perpendicular to the longitudinal direction of the peripheral-portion honeycomb fired body is different from a cross-sectional shape perpendicular to the longitudinal direction of the center-portion honeycomb fired body, and

a cross-sectional area perpendicular to the longitudinal direction of the peripheral-portion honeycomb fired body is 0.9 to 1.3 times larger than a cross-sectional area perpendicular to the longitudinal direction of the center-portion honeycomb fired body.

A honeycomb structure is provided that includes one or more pillar honeycomb units each including inorganic particles and an inorganic binder and having multiple cells separated by cell walls, the cells extending from one end face to another end face of each of the honeycomb units along a longitudinal direction thereof, the honeycomb structure being characterized in that each of the cell walls supports a noble metal catalyst and a NOx occluding catalyst so that the amount of the noble metal catalyst is greater on the surface of the cell wall than in the center part of the thickness of the cell wall.

A ceramic fiber insulation material is disclosed. It is prepared from a precursor blend generally comprising a gelled colloid and a ceramic fiber filler. Other filler, e.g., other fiber of refractory material, is contemplated, particularly when mixed with ceramic fiber. The gelled colloid ban be formed such as by mixing a gelling agent with a colloid of inorganic oxide or by blending anionic colloid with cationic colloid. The gelling agent is typically nonionic and watersoluble. The blend is trowelable, pumpable and possesses excellent adhesive characteristics including. the ability to stick to most surfaces, including metal surfaces. The blend is also virtually shrink-free during drying and, after drying, can provide the insulation material.

A mixture suitable for firing to an oxide of the formula (II), Ba0.m(A1_2xCr_2y0₃), where 4.6 ≤ m ≤ 6.6; $\text{(x + y) = 1}$; and 0 ≤ y ≤ 0.5, said mixture comprising at least one of:

• (a) barium oxide;
• (b) a clean thermal precursor (as hereinbefore defined) of barium oxide, such as barium carbonate or barium hydroxide; and
• (c) barium mono-aluminate, Ba0.A1₂0₃;

• (A) alumina, A1₂0₃;
• (B) hydrated forms of alumina, such as boehmite, A1₂0₃.H₂0; and
• (C) a clean thermal precursor (as hereinbefore defined) of aluminium oxide;
  
  and, where y is not zero, with at least one of
• (D) chromium (III) oxide, Cr₂0₃;
• (E) hydrous chromium (III) oxide; and
• (F) a clean thermal precursor (as hereinbefore defined) of chromium (III) oxide,

Also disclosed is a grain mix suitable for forming refractory and/or ceramic articles prepared by comminuting either or both of:

• (a) The above mixture and (b) an oxide of the formula (II), Ba0.m(A1_2xCr_2y0₃), where 4.6 ≤ m ≤ 6.6; $\text{(x + y) = 1}$; and 0 ≤ y ≤ 0.5.

A preform for being embedded in a matrix material for making a composite material is made essentially of many short fibers stuck together by a quantity of dried binder. This preform has a first portion in which the fiber volume proportion is relatively high, a second portion in which the fiber volume proportion is relatively low, and a third portion, joining between the first portion and the second portion, in which the fiber volume proportion changes substantially continuously from its portion adjoining to the first portion to its portion adjoining to the second portion. Thereby, the characteristics of the composite material, such as its strength, heat and wear resistance, and machinability and workability and characteristics with respect to wear on a mating member, alter smoothly from the first portion to the second portion without any severe discontinuity, thus ensurIng that no points of weakness are caused. A method for making such a preform, and a composite material object manufactured using such a preform, which may be an engine piston, are also disclosed.

Filter aus Keramik mit offenzelliger Schaumstruktur, hergestellt durch Imprägnieren eines Polymerschaumes mit einem keramischen Schlicker enthaltend ein Phosphatbindemittel, Abpressen des überschüssigen Schlickers, Trocknen und Brennen des Schaummaterials bei Temperaturen von 1660⁰C und mehr, oder bei gleicher Verfahrensführung durch Anwendung eines Schlickers, enthaltend ein geliertes Aliminiumhydroxid und Brennen bei wenigstens 1093°C. Es resultieren Filter aus Keramik mit offenzelliger Schaumstruktur, wobei die Keramik im wesentlichen phosphatfrei ist und die einzelnen Kristalle der Keramik untereinander zusammengesintert sind. Die Filter eignen sich zur Filtration von Metallschmelzen und insbesondere zur Filtration von Eisen- und Stahlschmelzen.

Stable alkaline sols of anionic alumina hydrate may be made by calcining alumina trihydrate and milling the monohydrate produced under alkaline conditions. Alkaline sols containing both anionic alumina hydrate and anionic colloidal silica may be used for bonding refractory bodies.

Bauplatte aus Gips und einer teilweise darin eingepressten Umhüllung aus einem Mineral- und/ oder Glasfaservlies, das auf der dem Gips zugewandten Innenseite größere Poren aufweist als auf der Außenseite, wobei das Vlies wenigstens zwei Sorten Fasern enthält, die durch ein an sich bekanntes Bindemittel verklebt sind, wobei die Fasern des größeren Durchmessers auf der Innenseite angeordnet sind, und wobei das Bindemittel 30 - 85 Gew.-% Aluminium-Eisen- und/oder Siliciumhydroxyd enthält.