SCHUTZSCHICHTSYSTEM FÜR NICHTOXIDISCHE, SI-HALTIGE SUBSTRATE
    17.
    发明公开
    SCHUTZSCHICHTSYSTEM FÜR NICHTOXIDISCHE, SI-HALTIGE SUBSTRATE 有权
    保护性涂层系统的非氧化物,SI-有基板

    公开(公告)号:EP1554230A1

    公开(公告)日:2005-07-20

    申请号:EP03753334.6

    申请日:2003-09-30

    IPC分类号: C04B41/87 F01D5/28

    摘要: Only mullite, yttrium silicate and zirconium do not have sufficient protection against oxidation at high temperatures when they are used as protective layers for non-oxidic ceramics containing Si. A covering layer arranged thereon and known according to prior art for metallic substrates is generally unsuitable due to its thermal expansion coefficient and/or its chemical incompatibility as thermally induced stresses are created, leading to cracks and flaking of the covering layer. The invention relates to a protective layer system for a non-oxidic ceramic containing Si, said system comprising a first protective layer provided with an oxide containing Si, and a covering layer arranged on the protective layer. Said covering layer contains a compound which is impermeable to oxygen and has a thermal expansion coefficient of less than 9,0*10-6/K. One such protective layer system is suitable both as a heat insulating layer and as an anti-corrosion layer against oxygen and water vapour. Said layers can advantageously be embodied in an at least partially graduated manner. The combination of a mullite protective layer and a lanthanum hafnate or a hafniumorthosilicate covering layer has proven to be especially advantageous.