A sintered material includes a first phase and a second phase, wherein the first phase is composed of cubic boron nitride particles, and the following relational expressions are satisfied when more than or equal to two cubic boron nitride particles adjacent to and in direct contact with each other among the cubic boron nitride particles are defined as a contact body, Di represents a length of an entire perimeter of the contact body, n represents the number of contact locations at which the cubic boron nitride particles are in direct contact with each other, d.sub.k represents a length of each of the contact locations, and Σd.sub.k (where k=1 to n) represents a total length of the contact locations: Dii=Di+(2×Σd.sub.k (where k=1 to n)); and [(Dii−Di)/Dii]×100≤50.

A sintered body containing polycrystalline grains of a metal oxynitride containing at least two metal elements, wherein Ba and at least one metal element of a crystal phase of the sintered body are contained in a triple point that is not a void between the polycrystalline grains. A method for producing the sintered body includes sintering a mixture of at least a metal oxynitride as a main component and a sintering aid containing cyanamide in an atmosphere containing nitrogen or a rare gas or in a reduced-pressure atmosphere of 10 Pa or less while applying a mechanical pressure with a retention time at a maximum heating temperature during the sintering set to 1 minute to 10 minutes.

One aspect of the present invention is a composite including: a porous boron nitride sintered body; and a resin filled in pores of the boron nitride sintered body, wherein the boron nitride sintered body has an average pore diameter of 3.5 μm or less.

Methods and systems for manufacturing a ceramic or glass material component supersaturated in nitrogen are disclosed. The method for manufacturing a component typically comprises receiving the ceramic or glass material within a containment vessel; simultaneously heating and applying isostatic pressure to the ceramic or glass material within the containment vessel to a first temperature and a first pressure using pressurizing nitrogen gas; holding the first temperature and the first pressure for a period of time; cooling the ceramic or glass material within the containment vessel to a second temperature while maintaining the first pressure; and depressurizing the containment vessel to a second pressure.

To provide a surface-coated cutting tool exhibiting excellent wear resistance in a high-speed cutting process and having prolonged service life. The surface-coated cutting tool includes a tool substrate containing WC crystal grains and insulating grains, and a coating layer composed of a multiple nitride of Ti, Al, and V and disposed on the surface of the tool substrate. The multiple nitride is represented by a compositional formula: Ti.sub.aAl.sub.bV.sub.cN satisfying the following relations:

0.25≤a≤0.35,

0.64≤b≤0.74,

0<c≤0.06, and

a+b+c=1

(wherein each of a, b, and c represents an atomic proportion). The coating layer is characterized by exhibiting a peak attributed to a hexagonal crystal phase and a peak attributed to a cubic crystal phase as observed through X-ray diffractometry.

A sintered body includes a crystal grain containing silicon nitride, and a grain boundary phase. If dielectric losses of the sintered body are measured while applying an alternating voltage to the sintered body and continuously changing a frequency of the alternating voltage from 50 Hz to 1 MHz, an average value ε.sub.A of dielectric losses of the sintered body in a frequency band from 800 kHz to 1 MHz and an average value ε.sub.B of dielectric losses of the sintered body in a frequency band from 100 Hz to 200 Hz satisfy an expression |ε.sub.A−ε.sub.B|≤0.1.

A cubic boron nitride (cBN)-based composite including about 30-65 vol. % cBN, about 15-45 vol. % titanium (Ti)-containing binders, about 2-20 vol. % zirconium dioxide (ZrO.sub.2), about 3-15 vol. % cobalt-tungsten-borides (Co.sub.xW.sub.yB.sub.z), and about 2-15 vol. % aluminum oxide (Al.sub.2O.sub.3).

This invention provides resin formulations which may be used for 3D printing and pyrolyzing to produce a ceramic matrix composite. The resin formulations contain a solid-phase filler, to provide high thermal stability and mechanical strength (e.g., fracture toughness) in the final ceramic material. The invention provides direct, free-form 3D printing of a preceramic polymer loaded with a solid-phase filler, followed by converting the preceramic polymer to a 3D-printed ceramic matrix composite with potentially complex 3D shapes or in the form of large parts. Other variations provide active solid-phase functional additives as solid-phase fillers, to perform or enhance at least one chemical, physical, mechanical, or electrical function within the ceramic structure as it is being formed as well as in the final structure. Solid-phase functional additives actively improve the final ceramic structure through one or more changes actively induced by the additives during pyrolysis or other thermal treatment.

The present invention provides a silicon nitride sintered substrate capable of reducing contamination caused by a boron nitride powder or the like used as a releasing agent and problems in bonding strength and dielectric strength at the time of laminating metal layers or the like, where the contamination is caused by a network structure provided by a silicon nitride crystal formed on the surface of the substrate in an unpolished state after sintering a silicon nitride powder. The silicon nitride substrate in an unpolished state after sintering is a silicon nitride sintered substrate where a cumulative volume of pores having a diameter in a range of 1 to 10 μm is not more than 7.0'10.sup.−5 mL/cm.sup.2 in a measurement by a mercury porosimetry. Preferably, Ra of the surface is not more than 0.6 μm and arithmetic mean peak curvature (Spc) of a peak is not more than 4.5 [l/mm].

A filter for the filtration of a fluid, such as a liquid, includes or is constituted by a support element made from a porous ceramic material, at least a portion of the surface of the support element being covered with a porous membrane separating layer, the membrane separating layer being constituted essentially of silicon carbide (SiC), its porosity being between 10% and 70% by volume, the median diameter of its pores being between 50 nanometers and 500 nanometers, its mean thickness being between 1 micrometer and 30 micrometers, and its tortuosity being less than 1.7.