SI3N4-BASED CERAMICS HAVING SUPERIOR CORROSION AND EROSION RESISTANCE

摘要

PURPOSE:To improve the corrosion and erosion resistances of Si3N4-based ceramics by forming a surface layer contg. a small amt. of a binding phase on the surface of the ceramics and by rendering such a gradient that the amt. of the binding phase increases toward the interior. CONSTITUTION:Si3N4-based ceramics is coated with a surface layer having such a gradient that the amt. of a binding phase increases from the surface toward the interior. The thickness of the surface layer is 5-100mum. The amt. of the binding phase at the top of the surface layer is limited to <=0.5vol.%. The resulting Si3N4-based ceramics has superior heat and erosion resistances and develops numerous uses.