Electrical characterization and test stand for heating elements

Defined electrical properties of ceramic powders are an important quality criterion in the manufacture of ceramic materials for electrical applications such as insulators, electrical heating conductors, varistors, PTC ceramics, or ceramic sensors. In addition, electrical properties are a sensitive indicator of the structural characteristics, impurities, and surface properties of powders, especially ceramic powders.

Fraunhofer IKTS has unique test benches that can be used to determine specific properties of electrically functional materials, especially structural ceramics. In addition to describing electrical conduction processes, temperature-dependent measurement of electrical resistance under defined atmospheric conditions makes it possible to indirectly identify and quantify processes such as oxidation, phase transformations, and crack formation with a high degree of accuracy and sensitivity. Impedance measurements on ceramic powders also allow conclusions to be drawn about grain sizes, surfaces, impurities, and crystal phases in the powder, thus providing valuable information for quality assessment of these powders before the actual start of ceramic production.

Services offered

• Precise determination of electrical resistance or electrical conductivity in a wide range using the 2- or 4-point method up to 1400 °C
• Measurement of charge carrier concentration, charge carrier type, and Seebeck coefficients as a function of temperature 
• Measurement under argon, nitrogen, and hydrogen-containing inert gases as well as in air atmosphere 
• Impedance spectra on ceramic powders and test specimens for easy quality assessment

Test stand for heating elements

Electric heating elements are used in numerous industrial processes. In addition to metallic heating conductors, electrically conductive ceramics play an important role. Ceramic materials offer many advantages, especially in high-temperature environments with corrosive and chemically reactive atmospheres. In our heating conductor test benches, we examine materials or heating elements with regard to their operating behavior under varying voltages, temperatures, heating and cooling scenarios in inert, air or high-vacuum atmospheres. In doing so, we record electrical parameters, power consumption, heating element temperature and time-dependent changes in these parameters, the functionality of contacts and interactions with insulation materials.

Technical equipment

High vacuum heating conductor test stand

• Voltages up to 10 V AC
• Currents up to 3000 A AC
• Measurement under high vacuum to 2·10^-6 mbar
• Temperature-time programs up to max. 2200 °C
  

Normal pressure heating conductor test stand

• Voltages up to 400 V AC
• Currents up to 600 A AC
• Measurement under air, nitrogen or argon
• Temperature-time programs up to max. 1600 °C