摘要:
A method for producing a highly uniform and highly dense sintered cubic boron nitride compact having high hardness by sintering at a milder condition without a binder, is provided. The method includes deflocculating secondary particles in cubic boron nitride starting powders by dispersing the starting powders in a solution of a deflocculant; molding the green compact after removing the solution of the deflocculant from the starting powders; and then sintering the green compact in the presence of a supercritical fluid source in a supercritical state by pressing and heating the green compact together with the supercritical fluid source. The supercritical fluid source can be one or more selected from a group consisted of polyvinylidene chloride, polyvinyl chloride, polyethylene, polypropylene, polystyrene, a polyester and an ABS resin. In the sintering, the pressure is 5 GPa or higher, and the temperature is 1400° C. or higher. According to the method, a highly uniform and highly dense sintered cubic boron nitride sintered compact having high hardness, can be obtained.
摘要:
An insulating material having structures and a design that maximizes vacuum area relative to material volume and minimizes the area of contact to a region to be insulated in order to provide maximum thermal resistance between the contacted area and an external environment is provided.
摘要:
A method of manufacturing an injection molding substance and the injection molding substance is provided. The method of manufacturing an injection molding substance including: providing a molding compound including a powder; making an intermediate mold by injection molding using the molding compound; cutting a portion of the intermediate mold; and sintering the cut intermediate mold.
摘要:
Multiphase polymeric binders for binder assisted forming of sinterable powder bodies are formulated to demonstrate improved rheological properties in the form of newtonion or near newtonion flow behavior thereby reducing dependence of binder viscosity on shear by tailoring the molecular weight and molecular weight distribution of the polymeric binder phases and the resulting polymer admixtures of the invention demonstrate shear rate independent behavior. Reduction of interfacial tension between binder phases by introduction of at least one macromolecule with separate segments selected to be compatible with the individual phases of the binder further increases processing performance as does use of polymer macromolecules having attributes that allow them to act as surface active materials at the interface of the sinterable powder and the multiphase binder composition. Predispersion of the surface active materials in the powder is facilitated by emulsification thereof in water prior to admixture with the powder.
摘要:
A method for electrospinning nanofibers having a core-sheath, tubular, or composite structure is disclosed. The process uses a spinneret having first and second capillaries that channel first and second fluids in the spinneret, the second capillary surrounding the first. A high voltage is applied between the spinneret and a spaced conductive collector. In one embodiment, the first fluid is a mineral oil and the second fluid is a polymeric solution that may include a polymer, a catalyst, a solvent, and a sol-gel precursor. The as-spun nanofiber includes an oil core and a composite sheath. The oil may be removed to produce a composite tubular fiber or the polymer and oil may be removed by calcination to produce a ceramic tubular fiber. In other embodiments, miscible fluids are used to produce porous nanofibers, selected additives functionalize the surfaces of the nanofibers and/or conjugated polymers are used.
摘要:
A honeycomb formed article comprising a plurality of partition walls is prepared using clay mainly composed of a ceramic material, a partition wall strengthening agent obtained by mixing a partition wall strengthening material with a dispersion medium mainly composed of an amphipathic liquid compound having both hydrophilic and hydrophobic groups is coated to a plurality of partition walls existing in at least one cell opening end portion of the formed article, and thereafter the article is fired. According to this method, while largely improving enhancement of productivity and product cost reduction, a honeycomb structure superior in isostatic strength and resistance to erosion can be stably obtained.
摘要:
A ceramic structure which is pollucite-based and has high refractoriness and high resistance to thermal shock. The inventive structure is suitable in high temperature applications such as a filtering particulates from diesel engine exhaust.
摘要:
A ceramic pin heating element having exterior heating conductors and integrated electrical connection surfaces, and method for making same. A first body is injection molded from a first injection-moldable ceramic composite compound having a first electrical resistance, and a second body is injection-molded from a second injection-moldable ceramic composite compound having a second electrical resistance about the first body so as to form a compound body. The compound body is then sintered. The resulting ceramic pin heating element is directly formed without additional steps for protecting (insulating) the element so as to prevent the exterior, complementary heating conductors from contacting the housing and/or terminal bolts. The danger of breakage of the pins at the mounting location and/or at the seal seat through variations in the thickness of contact and/or insulation coatings is minimized.
摘要:
A ceramic pin heating element having exterior heating conductors and integrated electrical connection surfaces, and method for making same. A first body is injection molded from a first injection-moldable ceramic composite compound having a first electrical resistance, and a second body is injection-molded from a second injection-moldable ceramic composite compound having a second electrical resistance about the first body so as to form a compound body. The compound body is then sintered. The resulting ceramic pin heating element is directly formed without additional steps for protecting (insulating) the element so as to prevent the exterior, complementary heating conductors from contacting the housing and/or terminal bolts. The danger of breakage of the pins at the mounting location and/or at the seal seat through variations in the thickness of contact and/or insulation coatings is minimized.
摘要:
Molding compositions including polyhydroxyalkanoates are provided. The use of polyhydroxyalkanoates as a binder in molding compositions provides improved binder removal in the finished molded product, and offers a wide range of physical properties suitable for use in a variety of processing conditions. The composition preferably includes a powdered material, such as a metal powder, ceramic powder, or blend, admixed with a polyhydroxyalkanoate binder. The compositions are useful in powder processing techniques, such as injection molding, slip casting, tape casting, or extrusion.