Molds ceramic matrix

Chem. Descrip. Boron nitride CAS 10043-11-5 EINECS/ELINCS 233-136-6 Uses Lubricant, filler for elec, insulating/thermally conductive materials, polymer matrixes, adhesives, pastes, potting compds., EP lubricants, refractories, refractory coatings, mold/die release, metal/ceramic and ceramic/matrix composites... 

Micro-milling of tool-steel microinjection molds Machining of microsurgical equipment Machining of optical glass and fibers components Machining of metal and ceramic matrix composite components... 

Resin transfer molding can be used to produce near net shape ceramic matrix composites, followed by pyrolysis [154]. 

Sherwood WJ, Whitmarsh CK, Jacobs JM, Interrante LV, Low cost near net shape ceramic matrix composites using resin transfer molding and pyrolysis. Ceramic Eng Sci Proc, 20th Annual Conference on Composites, Advanced Ceramics, Materials and Structures-B, Cocoa Beach, 174-183, 1996. 

Hexagonal boron nitride is commonly synthesized as a fine powder. Powders will vary in crystal size, agglomerate size, purity (including % residual BjOj) and density. BN powders can be used as mold release agents, high temperature lubricants, and additives in oils, rubbers and epoxies to improve thermal conductance of dielectric compounds. Powders also are used in metal- and ceramic-matrix composites to improve thermal shoek and modify wetting eharaeteristies. 

The debinding of powder injection molding workpieces, which consist of about 60 vol.% of a solid matrix (metal or ceramic powders) and thermoplastic polymer binders, was examined by extraction with scC02 [1]. By this technique the debinding time could be reduced from 1-2 days for pyrolysis to 1-2 hours for SFE. 

Besides the continuous fibers, application of metallorganic polymers to heat-resistant coatings, dense ceramic moldings, porous bodies, and SiC matrix sources in advanced ceramics via polymer infiltration pyrolysis (PIP) have been developed. Novel precursor polymers have been synthesized and investigated for ceramics in addition to PCS (Table 19.1). For SiC ceramics, various Si-C backbone polymers have been synthesized. Their polymer nature (e.g., viscosity, stability, cross-linking mechanism, and ceramic yield) are, however, fairly different from PCS. On the other hand, polysilazane, perhydropolysilazane, polyb-orazine, aluminum nitride polymers, and their copolymers have been investigated... 

The elements can also be made by casting aqueous slurries. These two methods require prefiring at low temperatures so that they can be handled in an automated large scale process. Elements can also be injection molded similar to plastic parts, in which the ceramic powder is mixed into an organic matrix. This third method leads to a very robust green (unfired) stone that can be easily processed further without prefiring. 

All modem thermionic ionization detectors (TED) employ a solid surface, composed of a ceramic or glass matrix doped with an alkali metal salt in the form of a bead or cylinder, molded onto an electrical heater wire as the thermionic source [254,270,271]. 

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