A seal assembly for a gas turbine engine having a seal formed of a carbon material; and a seal seat positioned for rotation relative to the seal, wherein the seal and the seal seat each have a sealing surface which together define a sliding seal, and further having a carbon film on the sealing surface of the seal seat.

Ground surface comprising a substrate (110) having a Young's modulus of between 100 and 1000 GPa, and in which the ground surface has, on a working surface (120), a Vickers hardness of between 1300 and 10 000 kgf/mm.sup.2, and/or a surface coating forming the working surface, in which the surface coating contains amorphous carbon and/or titanium nitride and/or chromium nitride and/or tungsten carbide.

The disclosure describes techniques for infiltrating a CMC substrate with a first slurry to at least partially fill at least some inner spaces of the CMC substrate, where the first slurry comprises first solid particles, drying the first slurry to form an infiltrated CMC including the first solid particles, depositing a second slurry including a carrier material and second solid particles on a surface of the infiltrated CMC, where the second solid particles comprise a plurality of fine ceramic particles, a plurality of coarse ceramic particles, and a plurality of diamond particles, drying the second slurry to form an article having an outer surface layer comprising the second solid particles on the infiltrated CMC, and infiltrating the article with a molten infiltrant to form a composite article.

The disclosure describes techniques for infiltrating a CMC substrate with a first slurry to at least partially fill at least some inner spaces of the CMC substrate, where the first slurry comprises first solid particles, drying the first slurry to form an infiltrated CMC including the first solid particles, depositing a second slurry including a carrier material and second solid particles on a surface of the infiltrated CMC, where the second solid particles comprise a plurality of fine ceramic particles, a plurality of coarse ceramic particles, and a plurality of diamond particles, drying the second slurry to form an article having an outer surface layer comprising the second solid particles on the infiltrated CMC, and infiltrating the article with a molten infiltrant to form a composite article.

A superabrasive compact and a method of making the superabrasive compact are disclosed. A superabrasive compact may include a diamond table and a substrate. The diamond table may be attached to the substrate. The substrate may have a metric of being defined as a ratio of carbon content over tungsten carbide content, wherein the metric ranges from about 6.13% to about 7.5%.

A cutting element may include a substrate; and an ultrahard layer on the substrate, the substrate and the ultrahard layer defining a non-planar working surface of the cutting element such that the ultrahard layer forms a cutting portion and the substrate is at least laterally adjacent to the ultrahard layer. Another cutting element includes a pointed region having a side surface extending from the pointed region outer perimeter to a peak. An ultrahard material body forms a portion of the pointed region including the peak, and a base region extends a depth from the pointed region outer perimeter. The ultrahard material body has a height to width aspect ratio with the height and width measured between two points of the body having the greatest distance apart along a dimension parallel with a longitudinal axis (i.e., height) along a dimension perpendicular to the longitudinal axis (i.e., width).

A cutting element may include a substrate; and an ultrahard layer on the substrate, the substrate and the ultrahard layer defining a non-planar working surface of the cutting element such that the ultrahard layer forms a cutting portion and the substrate is at least laterally adjacent to the ultrahard layer. Another cutting element includes a pointed region having a side surface extending from the pointed region outer perimeter to a peak. An ultrahard material body forms a portion of the pointed region including the peak, and a base region extends a depth from the pointed region outer perimeter. The ultrahard material body has a height to width aspect ratio with the height and width measured between two points of the body having the greatest distance apart along a dimension parallel with a longitudinal axis (i.e., height) along a dimension perpendicular to the longitudinal axis (i.e., width).

A composite material can include: a substrate of a first reaction-bonded silicon carbide (first RB-SiC) material; and a reaction-bonded diamond-retaining silicon carbide (RB-DSiC) layer bonded to a surface of the substrate. In some aspects, the RB-DSiC layer includes diamond particles bonded with a second reaction-bonded silicon carbide (second RB-SiC) material. The diamond particles may be homogeneously distributed through the second RB-SiC or only at the surface thereof. The diamond particles can be in an ordered pattern or un-ordered pattern. For example, a CMP conditioning disc can include the composite material of one of the embodiments.

A composite material can include: a substrate of a first reaction-bonded silicon carbide (first RB-SiC) material; and a reaction-bonded diamond-retaining silicon carbide (RB-DSiC) layer bonded to a surface of the substrate. In some aspects, the RB-DSiC layer includes diamond particles bonded with a second reaction-bonded silicon carbide (second RB-SiC) material. The diamond particles may be homogeneously distributed through the second RB-SiC or only at the surface thereof. The diamond particles can be in an ordered pattern or un-ordered pattern. For example, a CMP conditioning disc can include the composite material of one of the embodiments.

A cutting tool, including a silicon nitride (Si.sub.3N.sub.4) ceramic substrate, and a diamond film coated on the surface of the Si.sub.3N.sub.4 ceramic substrate. The diamond film has a thickness of 7-12 μm. The cutting tool includes a tool nose, a blade, and a handle. The blade has a rake angle γ of 5-15°, a clearance angle α of 10-14°, and a helix angle of 15-45°. The blade includes four cutting edges.