BIOLOX delta Ceramic Design Rationale

Hip Product Group

Culmination of over 30 years of ceramics research

BIOLOX delta represents the most recent advance in the evolution of alumina ceramic for orthopedic applications—providing the well-known advantages of previous generation alumina ceramics along with innovative toughening mechanisms. (Table 1)

Combines strength and toughness

As a composite of alumina and zirconia, BIOLOX delta combines the excellent hardness and wear properties of alumina with the superior fracture toughness properties associated with zirconia. [1,2]

Table 1: Improvements over 3 generations of alumina ceramics3
Year introduced 1974 1995 2004
4-point bending strength
500 (45) 631 (38) 1384 (67)
Fracture toughness K10
3.0 (0.45) 3.2 (0.4) 6.5 (0.3)
Hardness HV1
20 20 19

Optimized composition and microstructure

Material scientists optimized the chemical composition and microstructure (Figure 1) to design a material with excellent wear and mechanical properties. [1,2]

Figure 1: SEM of BIOLOX delta microstructure

Toughening Mechanisms

The toughness of a material refers to its ability to resist the propagation of cracks. BIOLOX delta utilizes two strategies to improve toughness [2]:

  • Crack deflection: The elongated platelet grains deflect and halt microcracks.
  • Transformation toughening: Zirconia nanoparticles increase slightly in volume when triggered by nearby microcrack, providing an obstacle to crack propagation.

† BIOLOX delta is a registered trademark of Cerasiv GmbH Innovatives Keramick-Engineering and CeramTec AG Innovative Ceramic Engineering.

  1. Masson B. Emergence of the alumina matrix composite in total hip arthroplasty. International Orthopaedics 2009; 33(2): 359-363.
  2. Kuntz M, Shneider N, Heros R. Controlled Zirconia Phase Transformation in BIOLOX® delta — a Feature of Safety. In Bioceramics and Alternative Bearings in Joint Arthroplasty. 10th BIOLOX Symposium Proceedings. (eds. D’Antonio JA, Dietrich M) Steinkopff Verlag, Darmstadt, 2005; 79-83.
  3. CermTec AG. BIOLOX delta nanocomposite for arthroplasty The fourth generation of Ceramics: Scientific information and performance data. [Brochure] Retrieved from