Injection silicon carbides

Bruch J, Rehn B, Song W, et al Toxicological investigations on silicon carbide. 2. In vitro cell tests and long term injection tests. BrJlndMed 50 807-813, 1993... 

Other linear polysilanes can also be used as ceramic precursors. Solid objects of silicon carbide are manufactured by Nippon Soda Co. from polysilastyrene and finely divided silicon carbide powder.133 These materials are blended, injection molded to the... 

Peugeot Fuel additive, ignition temperature 450 °C. Increase of exhaust temperature by exhaust port injection. Filter material silicon carbide... 

Sintered silicon carbides are formed by all the traditional methods as well as standard plastic forming techniques such as injection molding. These compacts are sintered with small amounts of additives at very high temperatures in inert atmospheres to form essentially a single phase silicon carbide structure. 

Because axial turbine rotors made of Si3N4 are still not completely reliable, research efforts continue to focus both on improving injection molding techniques and on strengthening the silicon nitride material systems. A ee-ramic composite of Si3N4 reinforced with silicon carbide whiskers may reduce structural failures and provide better high-temperature performance than monolithic ceramic parts. 

Polymers are nsed in fnel cells. Those of particular interest are the polymer electrolyte membrane (PEM) and the phosphoric acid fuel cell (PAFC) designs. The latter design contains the liquid phosphoric acid in a Teflon bonded silicon carbide matrix. In March 2005 Ticona reported that it had bnilt the first fnel cell prototype made solely with engineering thermoplastics. They claimed that this approach rednced the cost of the fuel by at least 50% when compared with fuel cells fabricated from other materials. The 17-cell unit contains injection moulded bipolar plates of Vectra liquid crystal polymer and end plates of Fortron polyphenylene sulfide (PPS). These two materials remain dimensionally stable at temperatures up to 200 "C. The Vectra LCP bipolar plates contain 85% powdered carbon and are made in a cycle time of 30 seconds. 

Taso, I., Danforth, S. C, and Metzner, A. B., Rheological behaviour of injection-moldable silicon powder-silicon carbide whisker formulations, J. Am. Ceram. Soc. 76(12) 2977 (1993). 

The reverse action also occurs, e.g., entry of PP into a chemical reaction with copper alloys, and hence with copper/beryllium. This reaction may cause the surface of a copper/beryllium component to become corroded [9], with the moulded parts being contaminated by alloy molecules. At the same time macromolecules of plastic are damaged through the catalytic action of copper on molten PP. Copper/beryllium nozzles for injection of PP should have a nickel or silicon carbide coating. 

Copper/beryllium alloys (thermal conductivity 200 W/mK) and copper/cobalt/ beryllium alloys (225 W/mK) for nozzle casings and tips in applications up to aromid 280 C (see Figure 4.5a) (because of the mechanical strength of the alloy, which rapidly falls when the temperature rises). Treatment involving an overlayer of silicon carbide increases injection abrasion resistance with, for example, PA and GF. Nickel coating eliminates the influence of copper on the melt (electroless nickel plating) ... 

This process is more popular in polymers. For the injection molding of ceramics, a thermoplastic polymer is required to the extent of 40 vol.%. This is called the binder. For example, to injection mold silicon carbide, ethyl cellulose is one such binder that is used. During the firing process, a binder removal soak, called binder burnout, is given to eliminate the polymer from the final product. 

Turbine blades have been made by injection moulding silicon carbide powders and are accurate to SOpm over the blade profile after ISZ linear... 

Sugano, T., Materials for Injection Moulding Silicon Carbide. Proceedings of the 1st Symposium on R S D for Basic Technology for Future Industry Fine Ceramics Project Japan Tech. Assoc. pp67-84 Tokyo (1983). 

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