Synthesis Of SiC Whiskers And Modified Resin

The dispersion of carbon black in silica sol and SiC whiskers synthesized by sol-gel method were studied. Meanwhile, the dispersion of carbon black in phenolic resin, the preparation of modified resin and the influence of modified resin on the properties of low carbon MgO-C brick were also discussed.SiC whiskers were synthesized with industrial silica sol and carbon black by sol - gel method. The influence of the dispersant on the dispersion of carbon black in silica sol was discussed; the effects of molar ratio of carbon black to silicon dioxide, the synthesis temperature and catalysts on the productivity of SiC whisker were also discussed. The results indicated that the degree of carbon black dispersion was the highest when the mass ratio of the carbon black to dispersant was 1:0.45. The synthesis temperature needed to form SiC above 1550℃and when the temperature reached 1600℃, the convertion process to form SiC was completed. When the molar ratio of carbon black to silicon dioxide was 3.3, the amount of SiC whiskers formed was the largest and the whiskers were also thinner and longer. SiC could be synthesized at a lower temperature when using Fe2O3 as a catalyst, but it affected the appearance of SiC formed.When using carbon black,B4C,nano-SiO2,phenolic resin,fused magnesite and graphite as main raw materials, the best dispersion of carbon black in phenolic resin and phenolic resin modified by carbon black,B4C,nano-SiO2 were revealed. On the base of the research, the influence of modified resin on the properties of low carbon MgO-C brick was discussed. The results indicated that degree of carbon black dispersion was the highest when the mass ratio of the carbon black:phenolic resin:dispersant was 1:4:0.7. Using carbon black or nano-SiO2 or the mixture of B4C and nano-SiO2 and carbon black as a modifier reduced the remaining carbon content of resin, but using B4C as a modifier increased the remaining carbon content of resin. Using modifiers improved the oxidation resistance of carbon resin. Low carbon MgO-C brick made using B4C modified resin as a binder showed excellect mechanical properties at normal temperature.