Ceramics (ceramic materials)

Ceramics (ceramic materials)

are non-metallic inorganic compounds formed from metallic (Al, Mg, Na, Ti, W) or semi-metallic (Si, B) and non-metallic (O, N, C) elements.

Atoms of the elements are held together in a ceramic structure by one of the following bonding mechanism: IonicBonding, Covalent Bonding, Mixed Bonding (Ionic-Covalent).

Most of ceramic materials have a mixed bonding structure with various ratios between Ionic and Covalent components. This ratio is dependent on the difference in the electro_ negativities of the elements and determines which of the bonding mechanisms is dominating ionic or covalent.

– Materials engineering is an engineers’ science, and thus considers not only the chemical composition, structure and properties of solids, but also their method of preparation. It is therefore appropriate to split into two each of the three categories put forward by materials science and separate natural materials from synthetic materials. Organic materials are then differentiated into natural products (like wood) and synthetic products (like most polymers) Metallic materials distinguish the rare native metals (gold, sometimes copper) from all metals and alloys that are derived from industrial processes. Finally, inorganic and non-metallic materials, classify on one side minerals and on the other rocks and ceramics or, more exactly, the triplet: ceramics + glasses + hydraulic binders (cement and plaster are examples of hydraulic binders).

–       P?F?HT: the manufacture of a ceramic component starts from a powdery medium (P), continues with its forming (F), and then ends with the heat treatments (HT). The consolidation of the material is done during sintering, therefore during the high temperature treatment;

–       – P?HT?F: the manufacture of a glass component also starts with the powdery medium (P), but this is followed by heat treatments (HT), which must result in melting, whereas the consolidation occurs at the end of the process, at the time of the solidification of the magma on cooling, therefore at the same time as the forming of the object (F);