抄録
Conditions for CVD of an SiO2 single coating and an SiO2/Si double coating to the inner walls of alloy tubes were examined in order to obtain a material that would resist corrosion by concentrated H2SO4 at 1173K. Uniform SiO2 films were coated on Incolloy 800 from Si(O-Et)4-N2-O2-Ar at 1053-1073K under 9.2KPa. Si undercoating films obtained from SiH4-Ar at 903K under 6.6KPa followed by annealing at 1273K markedly improved the adhesion of the film to substrate. The SiO2-Si coated Incolloy 800 tubes exhibited high resistance to corrosion by concentrated H2SO4 at 1173 K for 10h. EPMA line-analysis showed that the Si undercoating films turned to Si-Ni-Cr-Fe alloy during annealing and the alloy then changed to metal and SiO2 film during CVD of SiO2.
