Multifunctional Boron Nitride nanotube-Boron Nitride (BN—BN) nanocomposites for energy transducers, thermal conductors, anti-penetrator/wear resistance coatings, and radiation hardened materials for harsh environments. An all boron-nitride structured BN—BN composite is synthesized. A boron nitride containing precursor is synthesized, then mixed with boron nitride nanotubes (BNNTs) to produce a composite solution which is used to make green bodies of different forms including, for example, fibers, mats, films, and plates. The green bodies are pyrolized to facilitate transformation into BN—BN composite ceramics. The pyrolysis temperature, pressure, atmosphere and time are controlled to produce a desired BN crystalline structure. The wholly BN structured materials exhibit excellent thermal stability, high thermal conductivity, piezoelectricity as well as enhanced toughness, hardness, and radiation shielding properties. By substituting with other elements into the original structure of the nanotubes and/or matrix, new nanocomposites (i.e., BCN, BCSiN ceramics) which possess excellent hardness, tailored photonic bandgap and photoluminescence, result.

cubic boron nitride sintered material including 90.0% by mass or more and 99.5% by mass or less of cubic boron nitride and 0.5% by mass or more and 10.0% by mass or less of silicon, wherein the cubic boron nitride sintered material has a total content of the cubic boron nitride and the silicon of 94.0% by mass or more and 100% by mass or less.

An article includes a substrate, an intermediate coating on the substrate, and an environmental barrier coating (EBC) on the intermediate coating. The substrate includes a ceramic, ceramic matrix composite (CMC), or superalloy. The EBC includes a rare earth disilicate. When the intermediate coating is at an initial state, such as prior to exposure to an oxidating environment, the intermediate coating includes a bond coat on the substrate and a reactive layer on the bond coat. The bond coat includes silicon, while the reactive layer includes a rare earth monosilicate or rare earth oxide. In response to oxidation of a portion of the silicon of the bond coat to form silicon dioxide, a portion of the rare earth monosilicate or rare earth oxide of the reactive layer is configured to react with at least a portion of the silicon dioxide to form a converted layer that includes a rare earth disilicate.

Disclosed herein is a ceramic matrix composite comprising a preform comprising a plurality of plies; a ceramic matrix encompassing the plies and distributed through the plies; and thermally conducting particles distributed through the ceramic matrix. Disclosed herein is a method comprising distributing thermally conducting particles between plies in a preform; infiltrating chemical vapors of a ceramic precursor into the plies; and reacting the ceramic precursor to form a matrix.

A composite polycrystal includes: a polycrystalline diamond phase including a plurality of diamond particles; and non-diamond phases composed of non-diamond carbon. The non-diamond phases are distributed in the polycrystalline diamond phase. An average value of projected area equivalent circle diameters of the non-diamond phases is not more than 1000 nm.

A method of fabricating a laminar composite article, includes steps of spreading a plurality of continuous fiber tows from a spool to form a first ply layer having a substantially consistent layer thickness, applying a binder to the spread plurality of continuous fiber tows, curing the plurality of continuous fiber tows and applied binder at a cure temperature less than a thermal decomposition temperature of the binder, and processing the cured plurality of continuous fiber tows at a post-cure temperature greater than the cure temperature.

The honeycomb structure includes a honeycomb structure body and a pair of electrode members disposed on a side surface of the honeycomb structure body, each of the pair of electrode members is shaped in the form of a band extending in a cell extending direction, and in a cross section perpendicular to the extending direction of cells, one electrode member is disposed on a side opposite to the other electrode member via a center of the honeycomb structure body, one or more slits opened in the side surface are formed in the honeycomb structure body, the honeycomb structure body has a charging material charged into the at least one slit, the charging material contains aggregates and a neck material, and a ratio (α2/α1) of a thermal expansion coefficient α2 of the charging material to a thermal expansion coefficient α1 of the honeycomb structure body is from 0.6 to 1.5.

An injection system comprises a fluid control member and a reciprocating member; wherein the fluid control member is configured to form a carbon composite-to-metal seal with the reciprocating member in response to application of a compressive force; the carbon composite comprising carbon and a binder containing one or more of the following: SiO.sub.2; Si; B; B.sub.2O.sub.3; a filler metal; or an alloy of the filler metal, and the filler metal comprising one or more of the following: aluminum; copper; titanium; nickel; tungsten; chromium; iron; manganese; zirconium; hafnium; vanadium; niobium; molybdenum; tin; bismuth; antimony; lead; cadmium; or selenium.

A honeycomb structure, including: a plurality of pillar shaped honeycomb segments, each of the pillar shaped honeycomb segments including a partition wall and a plugged portion; and a joining layer arranged so as to join side surfaces of the pillar shaped honeycomb segments to each other. The honeycomb structure satisfies the following equations (1) to (3):
y≤1000  (1);
y≤717.92x.sup.−0.095  (2); and
y≥462.4x.sup.−0.153  (3),
in which y is a maximum temperature (° C.) at which the use of the honeycomb structure is accepted, and x is a thermal conduction factor represented by the following equation:
thermal conduction factor=(thermal conductivity of the partition wall×thermal conductivity of the joining layer)/(average thickness of the joining layer×porosity of the partition wall).

The present invention provides a sealing member which includes a substrate including silicon carbide; and a plurality of cylindrical or polygonal columnar graphites dispersed in the substrate, and a method for manufacturing the same.