Breviary Technical Ceramics


      Werkstoffe der technischen Keramik




3.4.3 Non-oxide Ceramics

Analogous to the oxide ceramics, the non-oxide ceramics are made exclusively from synthetic raw materials. The term non-oxide ceramics generally refers to carbides, nitrides or oxynitrides. The non-oxide ceramics are characterised by their truly unusual properties, as will be seen in the following material descriptions. The high proportion of covalent bonds in the carbide and nitrides crystal structures is responsible for the remarkable combination of properties. Oxide crystal structures, in contrast, have a relatively high proportion of electrovalent bonds. This also implies that the process from raw material powder to manufactured part is more costly than for oxide ceramics. The raw materials generally have to be extremely fine-grained, and the sintering process requires an absolutely oxygen-free atmosphere. This implies firing in a vacuum or inert gas in a gas-tight furnace at temperatures that can reach well over 2,000° C!


Vom Formen und Sintern
Kap. 4
Bindungsarten und Festigkeit
Kap. 10


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