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Rubalit® ZTA

Zirconia Toughened Alumina Substrates

New in 2023: Substrates made of zirconia toughened alumina (Rubalit® ZTA) impress with their high flexural strength (625MPa), increased reliability (thermocycling) and a dielectric strength of AC: ≥ 25 kV/mm. ZTA is used in industrial applications, xEV (electric vehicles) as well as in the renewable energy sector.

Zirconia reinforced alumina substrates in front of a flash.

In May 2023, the substrate Rubalit® ZTA was added to CeramTec's comprehensive product portfolio. ZTA is a mixed ceramic - consisting of aluminium oxide ceramic, which in turn is toughened with zirconium oxide particles. This combination has improved the properties of pure aluminium oxide. Increased fracture toughness, flexural strength and dielectric strength make the Rubalit® ZTA substrate more resistant to mechanical stress.

The thermal conductivity is more than 26 W/mK and the dielectric strength reaches 25 kV/mm. This makes Rubalit® ZTA significantly superior to common PCB materials, for example. Its thermal conductivity, temperature resistance and insulation properties also make the substrate an ideal material for use in passive components or chip resistors.

Interested? David Hassler, Product Manager E-Mobility at CeramTec, explains in a short interview why manufacturers of power electronics need the new ceramic substrate Rubalit® ZTA.

Rubalit® ZTA Substrates

Key Advantages

Video shows properties of ZTA substrates
An electric car drives along a mountainous country road with wind turbines in the background.
Rubalit® ZTA - Performance for the Energy Transition

Technical Values & Parameters

Physical properties  

  • Density: > 3,95 g/cm3


Surface properties

  • Ra value: < 0,4 µm


Mechanical properties

  • Flexural strength (double ring): 625 MPa
  • Modulus of elasticity: 310 GPa
  • Vickers hardness: not specified


Thermal properties

  • CTE: ≥ 7.1 (≥ 8.0) 10-6/K at 20-300°C (300-600°C)
  • Specific heat capacity at 20°C: 0.62 J/gK
  • Thermal conductivity at 20°C: ≥ 21.0 W/mK

Electrical properties

  • Dielectric constant at 1 MHz: 12
  • Dielectric loss factor at 1 MHz: 10 10-3
  • Volume resistivity at 25 °C: 1014 Ohm cm
  • Dielectric strength: ≥ 20 kV/mm



  • 5,5 "x7,5" x 0,013" (190,5 x 138 x 0,32mm)


Substrate as fired

  • Length and width tolerance: +/- 1.5 
  • Thickness tolerance: +/- 12.5%

Download Datasheet

Substrate Data Sheet: Zirconia Reinforced Alumina ZTA
Material properties of ZTA

Ceramic Substrates Application Areas

List of materials and markets for CeramTec substrate solutions

Please click to enlarge

CeramTec Substrates in Comparison

MaterialFlexural strength
Thermal conductivity
Dielectric strength
Al2O34506 - 92215
AlN4504 - 617015
ZTA6257 - 92625
Si3N47002 - 48025


Technical Values