| 摘要 |
<p>A coated carbon body comprising (i) a carbon body having a converted porous layer formed thereon, and (ii) a glass forming coating, at least a portion of which is within the said converted layer. Method for the mfr. of the said carbon coated body comprising: a) forming a converted layer on the carbon body by converting a porous layer formed by etching and reacting the body with B2O3. The converted layer contains interconnecting interstices and B4C which is formed by reaction between the B2O3 and the carbon body, and b) applying a glass forming coating over the converted layer, at least a portion of which is within the said converted layer. An alternative method for the mfr. of the said carbon coated body comprises: a) forming the said converted layer on the carbon body; b) applying an intermediate glass forming coating over the converted layer, where the intermediate coating comprises Si or a Si-contg. cpd.; c) subjecting the body to a nitriding atmos. to convert the Si or Si-contg. cpd. to Si3N4, and d) applying an outer refractory coating over the intermediate coating. The glass forming layer comprises cpds. selected from Si3N4, SiON2 and mixts. thereof. The glass forming coating comprises a primary glass forming species selected from B, B4C, B2O3, Si, Si alloys, SiO2, GeO2 and mixts. thereof, and may also contain borides and oxides of Zr, Al, Mg, Hf, Ti, carbides of Zr, Hf, Ti, nitrides of Zr, Hf, Ti, Si and mixts. thereof. The refractory coating comprises carbides, borides or nitrides of Si, Zr, Ta, Hf, Nb and Ti, SiON2, AlB, AlN or mixts. thereof. The nitriding atmos. is selected from N2, NH3, N2H4 and mixts. thereof, and also contains O2 or an O-contg. cpd. to convert the Si or Si-contg. cpd. to an oxynitride of Si, where the O-contg. cpd. is H2O or CO/CO2. The glass forming coating is applied by CVD or by sol-gel technology. The converted layer is formed by heating to at least 1500 deg.C. The nitriding step is carried out at a temp. of 1350-1500 deg.C.</p> |
