The present invention provides a welding tool member for friction stir welding comprising a silicon nitride sintered body, wherein the silicon nitride sintered body includes an additive component other than silicon nitride in a content of 15% by mass or less, and the additive component includes three or more elements selected from Y, Al, Mg, Si, Ti, Hf, Mo and C. It is preferable that the content of the additive component is 3% by mass or more and 12.5% by mass or less. It is also preferable that the additive component includes four or more elements selected from Y, Al, Mg, Si, Ti, Hf, Mo and C. Due to above structure, there can be provided a welding tool member for friction stir welding having a high durability.

A method is provided for producing an article which is transparent to IR wavelength in the region of 4 μm to 9 μm. The method includes the steps of (a) Producing ultra-fine powders of ZnS, (b) followed by pretreatment of the ultra-fine powders under reduced gas conditions including H2, H2S, N2, Ar and mixtures there of (c) followed by vacuum (3×10.sup.−6 torr) treatment to remove oxygen and sulfates adsorbed to the surface disposing a plurality of nano-particles on a substrate, wherein said nanoparticles comprise ZnS with ultra-high purity of cubic phase; (b) subjecting the nano-particles to spark plasma sintering thereby producing a sintered ZnS product with IR transmission reaching 75% in the wavelength range of 4 μm to 9 μm.

A method is provided for producing an article which is transparent to near-wave IR, mid-wave and Long-wave multi-spectral and IR wavelength in the region of 0.4 pm to 16 μm. The method includes the steps of (a) Producing ultra-fine powder of CaLa.sub.2S.sub.4 via SPLTS process, (b) followed by pretreatment of the ultra-fine powder under inert and reducing gas conditions including H.sub.2 or Argon or N.sub.2 or H.sub.2/H.sub.2S, H.sub.2S, and mixtures there of (c) followed by sieving the powder in 140 mesh screen and cold pressing the powder at 7000 psi for 7 min. into a disk shaped green body (d) then Cold-Isostatic Pressing (CIP) at 40,000 psi for 5 min in a rubber mold (e) finally sintered article of CaLa.sub.2S.sub.4 disk of 25.4 mm diameter with ultra-high density containing cubic phase of CaLa.sub.2S.sub.4 to yield IR transmission of a peak value of 57% within the IR wavelength range of 2 μm to 16 μm, either by using microwave sintering followed by hot isostatic press or spark plasma sintering followed by hot isostatic press or vacuum sintering at (3×10.sup.−6 torr) followed by hot isostatic press or hot press sintering followed by hot isostatic press and finally followed by mirror polished IR article, is obtained.

The present disclosure relates to a method of making a powder of dense and spherically shaped cemented carbide or cermet granules. The present disclosure also relates to a powder produced by the method and use of said powder in additive manufacturing such as 3D printing by the binder jetting technique. Furthermore, the present disclosure relates to a Hot Isostatic Pressing (HIP) process for manufacturing a product by using said powder.

The invention relates to a method of manufacturing a ceramic molding, comprising the following steps: a) providing three or more ceramic powder layers that are arranged in layers, one on top of the other, to form a compression-molded element and sintering the compression-molded element obtained in step b) to form a ceramic molding, characterized in that the ceramic powder layers have different compositions, each ceramic powder layer comprising a mixture of at least two different base powders and each base powder containing at least 80 wt. % ZrO.sub.2 and at least 0.02 wt. % Al.sub.2O.sub.3, each weight amount being relative to the total weight of the constituents of the base powder.

The invention relates to a sintered molding with a color gradient for use in the manufacture of dental restorations, obtainable by sintering a compression-molded element comprising five or more different ceramic powder layers, each powder layer comprising at least two different base powders and each base powder containing at least 80 wt. % ZrO.sub.2, each weight amount being relative to the total weight of the base powder.

The disclosure relates to methods of fabricating of ceramic structures, and more particularly to methods of fabricating ceramic structures having profiled surfaces and more particularly to methods of fabrication of ceramic mirror blanks. In one embodiment, a method of forming a shaped ceramic article, includes: forming, via one of a cold-pressing process or pressure casting process, a green ceramic article comprising a first surface, an opposing second surface and at least one high aspect ratio feature shaped into at least one surface; heating the green featured ceramic part to form a debound featured ceramic part; and densifying the debound featured ceramic part via one of a pressureless sintering process or a hot-pressing process.

A method is provided for producing an article which is transparent to IR wavelength in the region of 4 μm to 9 μm. The method includes the steps of (a) Producing ultra-fine powders of ZnS, (b) followed by pretreatment of the ultra-fine powders under reduced gas conditions including H2, H2S, N2, Ar and mixtures there of (c) followed by vacuum (3×10.sup.−6 torr) treatment to remove oxygen and sulfates adsorbed to the surface disposing a plurality of nano-particles on a substrate, wherein said nanoparticles comprise ZnS with ultra-high purity of cubic phase; (b) subjecting the nano-particles to spark plasma sintering thereby producing a sintered ZnS product with IR transmission reaching 75% in the wavelength range of 4 μm to 9 μm.

A method of producing a cylindrical insulator for a spark plug includes a molding step of forming ceramic powder filled in a cavity defined by a mold and a molding pin into a compact. In a first removal step of removing the compact from the mold, the compact has at least one protrusion formed in at least one recess of the molding pin formed in an outer cylindrical surface of the molding pin, and the at least one protrusion is locked in the at least one recess, thereby allowing the compact to be removed with the molding pin from the mold. In a second removal step of removing the molding pin from the compact, the molding pin is turned or rotated in the circumferential direction about the compact, causing the at least one recess to cut the at least one protrusion from the compact, and thereafter the molding pin is removed from the compact.

The invention relates to the making, on a support plate (34), of an annular space (76) in a ceramic paste covering this plate, in order, by successive deposits and firing of layers of said ceramic paste, to create a base of a ceramic shell (40) for the moulding of parts, the base having said annular space (76). For this purpose, between two deposits of said ceramic paste, and on the plate, said deformable annular element (82) will be deformed in order to break the ceramic layer.