Technical ceramics

BCE RingZirkonoxid ist der Hochleistungswerkstoff unter den Oxidkeramiken. Er zeichnet sich durch außergewöhnliche Bruchzähigkeit, hohe Verschleißfestigkeit und Korrosionsbeständigkeit sowie eine niedrige Wärmeleitfähigkeit aus. Aluminiumoxid hingegen ist der am häufigsten eingesetzte keramische Werkstoff. Dank seiner sehr guten elektrische Isolierung, Durchschlagsfestigkeit und hohen Temperaturbeständigkeit bis hin zu 1750 °C ist er ideal für elektrische Anwendungen und Hochtemperatureinsätze. Die optimalen Eigenschaften aus beiden Werkstoffen sind in unseren Mischoxidkeramiken realisiert. Hier werden große Festigkeit und Zähigkeit mit Härte und Verschleißbeständigkeit kombiniert.

Zu unseren Sonderwerkstoffen zählen die sogenannten nichtoxidischen, keramischen Hochleistungswerkstoffe wie Siliziumnitrid und -carbid sowie Borkarbid und Aluminiumnitrid. Sie weisen ganz unterschiedliche Eigenschaften auf, die genau auf die jeweilige Anwendung zugeschnitten sind. In einer Vergleichstabelle sind alle relevanten Eigenschaften unserer Präzisionsbauteile aus Hochleistungskeramik aufgelistet.

Zirconia — ZrO2
Zirconia is most famous high-performance material among all oxide ceramics. Ceramic components made out of Zirconia generally consist of Zirconia as basic material doped with some percentage of other oxides like Yttria (Y2O3) or Magnesia (MgO). Depending on doping material different material properties could be achieved because of influencing the Yttria’s microstructure. The „ceramic steel“ titled Zirconia is doped with Yttria forming an ultra-fine ductile structure with sub-micron grain formation leading to enormous bending strengths. Magnesia doped qualities are less strong also showing a coarser microstructure.

Zirconia is characterized through its tribological performance (friction and wear) in moving applications and furthermore:

  • Excellent fracture toughness
  • Very good wear resistance
  • High corrosion stability
  • Low thermal conductivity
  • CTE in range of steel

All these properties characterize Zirconia (Yttria stab.) as a leading structure material for highest wear stress in several application fields, even medical technology.

Corresponding BCE qualities are Z 700 and Z 700 E, respectively the Magnesia-doped Z 507 material. For watch and jewelry industry Z 700 grade is also available in black. Further coulors on request.

Alumina — Al2O3
Alumina is the most popular ceramic material resulting from nearly endless availability in different purities, starting with approx. 92 % ending up with 99.99 % qualities and the specific material characteristics. Combining a medium level bending strength with excellent wear resistance, high hardness and relatively good thermal conductivity Alumina is versatile useable. Especially in electrical applications and high temperature operations the excellent insulating behavior and dielectric strength favor Alumina for use up to 1750 °C.

Hardness is paired with high brittleness, therefore Alumina is not suited in highly loaded machinery applications. From time to time a customizing and modification in design-engineering can succeed.

BCE treats purity grades in range from 96 % (A 960) to 99.99 % (A 999) — mainly the 99.5…99.7 % quality (A 995).

Mixed Oxides
Mixed oxides are manufactured by mixing together main components Alumina and Zirconia. Depending on particular percentage rate with typically 80 % to 90 % Alumina with rest Zirconia or the opposite way around material grades with main content Alumina are so called ZTA (Zirconia Toughened Alumina) or accordingly ATZ (Alumina Toughened Zirconia) with Zirconia as essential part.

Background for this material species is to combine the positive properties of both materials: the high bending strength and ductility of Zirconia with the hardness of Alumina. Using appropriate Alumina contents even the high electrically insulating behavior is not affected.

ATZ is used in special wear applications (e.g. drills for medical surgery and metal working processes) and ZTA for insulating components and medical technology instruments. Excellent surface qualities ensure lowest possible abrasive wear.

Special Materials
Embraced by the term special materials BCE summarizes all so called non-oxide high performance ceramics such as Silicon Nitride (Si3N4), Silicon Carbide (Si-infiltrated SiSiC or Silicon-free sintered SSiC), Boron Carbide (B4C) and Aluminium Nitride (AlN). All mentioned candidates offer different specific properties aiming for different fields of application. Silicon Nitride offers a high bending strength and fracture toughness likewise Zirconia material but showing a low CTE paired with high thermal conductivity.

The Carbides with excellent hardness values are competing mainly against Alumina (Al2O3) materials.

Aluminium Nitride is taking an exceptional position because of the extremely good thermal conductivity in range of 150…180 W/mK suited for high-performance electronic application, cruibles and so on.

Comparison Table
Comparison table precision components in high-performance ceramics

high performance ceramics comparison

Comparison table

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