SiC is a material with excellent strength, heat resistance, and corrosion resistance. It is generally used as a material for SiC invertors, semiconductor susceptors, edge rings, MOCVD susceptors, and mechanical bearings. Recently, SiC single crystals for LED are expected to be a new market application. In addition, SiC is also used as a heating element applied directly to electrical energy. Research in this study has focused on the manufacture of heating elements that can raise the temperature in a short time by irradiating SiC-I2 with microwaves with polarization difference, instead of applying electric energy directly to increase the convenience and efficiency. In this experiment, Polydimethylsilane (PDMS) with 1,2 wt% of iodine is synthesized under high temperature and pressure using an autoclave. The synthesized Polycarbosilane (PCS) is heat treated in an argon gas atmosphere after curing process. The experimental results obtain resonance peaks using FT-IR and UV-Visible, and the crystal structure is measured by XRD. Also, the heat-generating characteristics are determined in the frequency band of 2.45 GHz after heat treatment in an air atmosphere furnace.

In order to improve the high temperature oxidation resistance and lifespan of mat type porous carbon insulation, SiC was coated on carbon insulation by solution coating using polycarbosilane solution, curing in an oxidizing atmosphere at 200 oC, and pyrolysis at temperatures up to 1200 oC. The SiOC phase formed during the pyrolysis process was converted into SiC crystals as the heat treatment temperature increased, and a SiC coating with a thickness of 10-15 nm was formed at 1600 oC. The SiC coated specimen showed a weight reduction of 8.6 % when it was kept in an atmospheric environment of 700 oC for 1 hour. On the other hand, the thermal conductivity was 0.17W/mK, and no difference between states before and after coating was observed at all.

Cu-30 vol% SiC composites with relatively densified microstructure and a sound interface between the Cu and SiC phases were obtained by pressureless sintering of PCS-coated SiC and Cu powders. The coated SiC powders were prepared by thermal curing and pyrolysis of PCS. Thermal curing at 200 oC was performed to fabricate infusible materials prior to pyrolysis. The cured powders were heated treated up to 1600 oC for the pyrolysis process and for the formation of SiC crystals on the surface of the SiC powders. XRD analysis revealed that the main peaks corresponded to the α-SiC phase; peaks for β-SiC were newly appeared. The formation of β-SiC is explained by the transformation of thermally-cured PCS on the surface of the initial α-SiC powders. Using powder mixtures of coated SiC powder, hydrogen-reduced Cu-nitrate, and elemental Cu powders, Cu-SiC composites were fabricated by pressureless sintering at 1000 oC. Microstructural observation for the sintered composites showed that the powder mixture of PCS-coated SiC and Cu exhibited a relatively dense and homogeneous microstructure. Conversely, large pores and separated interfaces between Cu and SiC were observed in the sintered composite using uncoated SiC powders. These results suggest that Cu-SiC composites with sound microstructure can be prepared using a PCS coated SiC powder mixture.

Porous SiC beads were prepared by freeze-drying a polycarbosilane (PCS) emulsion. The water-in-oil (w/o) emulsion, which was composed of water, PCS dissolved p-xylene, and sodium xylenesulfonate (SXS) as an emulsifier, was frozen by dropping it onto a liquid N2 bath; this process resulted in 1~2 mm sized beads. Beads were cured at 200 oC for 1 h in air and heat-treated at 800 oC and 1400 oC for 1 h in an Ar gas flow. Two types of pores, lamella-shaped and spherical pores, were observed. Lamellar-shaped pores were found to develop during the freezing of the xylene solvent. Water droplets in the w/o emulsion were changed into spherical pores under freeze-drying. At 1400 oC of heat-treatment, porous SiC was synthesized with a low level of impurities.

Process conditions for the impregnation of polycarbosilane preceramic polymer into SiC-based composites were investigated. Two kinds of preceramic polymer (PCP) was impregnated into SiC-fiber fabrics with different solvents of n-hexane and divinylbenzene (DVB). Both microstructural observations and mechanical tests were conducted to evaluate the impregnation. The matrix phases were particulated in the case of hexane solvents. Apparent relative density of the matrix was about 78.8%. The density of matrix was increased to about 96.1-98.8% when the DVB was used; however, brittle fracture was observed during a bending test. The modulus of toughness was less than 0.74J/m3. The fabric impregnated with a mixed PCP-dissolved solution showed intermediate characteristics with relative high density of filling (apparent density of ~96.1%) as well as proper bending behavior. The modulus of toughness was increased to about 5.31J/m3. The composites developed by changing the precursor and solvent suggested the possibility of fabricating SiCf/SiC composites without a fiber to matrix interphase coating.