Breviary Technical Ceramics






3.4.1 Silicate Ceramics Technical Porcelain

Technical porcelains are understood to be materials in the "alkaline alumina silicate porcelain" (C 100) group, which find diverse applications in electronics.

As electricity began to be used in the home and industry, many types of porcelain were already available, offering excellent properties such as

  • high mechanical strength,
  • excellent electrical insulation properties and
  • outstanding resistance to chemical attack.

As energy consumption rapidly increased so did the needs of electrical technology, and the properties of porcelain were continually developed and improved. This led to today’s alumina porcelain, which exhibited noticeably greater strength and reliability even under extreme thermal stress (for example, -50 °C to 550 °C) or sudden temperature changes (during a short circuit for example), and was clearly superior to quartz porcelain. Even the long-term behaviour under open air conditions (ageing) of alumina porcelain is superior to that of quartz porcelain, and it is therefore used primarily in open air switching stations and for open-wire insulators (e.g., high tension or train insulators and supports) by quality-conscious users.
More recent developments indicate that hydrophobic surfaces improve the electrical properties of the outer layer, and permit simplified structural forms. The replacement of alumina with bauxite is a further innovation. This new and significantly more economical material offers comparable technical properties.

Alkali-Aluminiumsilikate (C100)

Figure 3: Microstructure of an alumina porcelain, ground and etched, under a scanning electron microscope

The difference between quartz porcelain and alumina porcelain lies in the exchangeable raw material, i.e. the more economical quartz (SiO2) and the relatively expensive alumina (Al2O3). For this reason, and because of the lower production costs, traditional quartz porcelain represents an economic alternative for moderate load applications. For a significant number of applications, this is thus a factor in quartz porcelain retaining market share and improving competitiveness.


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