Dielectric strength

Advanced ceramics offer superior dielectric properties compared to those of metals and plastics. Advanced ceramics are insulating materials: they do not conduct electrical currents. This physical property is called resistivity. Other electrical properties, such as dielectric strength, relative permittivity (or dielectric constant) and the loss angle, vary from one ceramic to the next.


Dielectric strength, also called breakdown strength, is the maximum voltage a material can withstand before generating an electrical arc on the surface or through the thickness of the material. Dielectric strength is measured in Kv/mm.

Advanced ceramics such as high-purity (≥94 %) alumina and aluminium nitride offer this characteristic, and to a lesser extent sintered silicon nitride. Silica, quartz and Macor are also very good insulating materials. Silicone carbides and zirconia do not offer good dielectric strength.

Application markets

These materials are used in a wide variety of business sectors: electronics, defence, medical, energy, transport, aeronautical and spatial, etc.

Comparative table of properties

Comparative table of electrical properties
Values at ambient temperature – 20°c


Dielectric strength (KV/mm) Dielectric loss factor (tan ɗ)

Dielectric constant



(94 to 99.8 % )

>1012 to 1015 17 to 40


to 3.10-5
9.5 to 11
Aluminium nitride


to 1013
16 to 20 0,5.10-3  
Sintered silicon nitride

> 1010

to 1011
15 - -


to 1018
25 to 40 10-3 to 10-4 3.7

These values are for information only and do not constitute a contractual obligation.

Raw material
Finished product

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