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On-X Carbon Properties

On-X carbon is an advanced form of pure, isotropic pyrolytic carbon that was developed and patented in 1992 by the founders of On-X Life Technologies, Inc. While originally developed for prosthetic heart valves, On-X carbon has properties that are desirable for a variety of devices.

On-X carbon has a toughness and flexural strength not achievable with the more brittle silicon-alloyed carbon. The purity and surface finish of On-X carbon provide maximum biocompatibility.

Typical Surface Properties of On-X carbon

Property Value
Critical Surface Tension (dynes/cm) 42
Surface Roughness Ra(nm) 33.9
Surface Chemistry Carbon (Atomic %) ~85
Surface Chemistry Silicon (Atomic %) 0
Surface Chemistry Oxygen (Atomic %) ~15

Typical Mechanical Properties of On-X carbon

Property Value
Wear Resistance 1.23x10 -6 mm 3 / km
Coefficient of friction 0.15
Young's Modulus (GPa) 26
Flexural Strength (MPa) 490
Density (gm/cm 3) 1.9
Strain to Failure (%) 1.6
Strain Energy (MPa-mm/mm) 7.7
Residual Stress (MPa) 18.2
Fracture toughness (MPa m 1/2) 1.67
Fatigue Threshold (MPa m1/2) 1.11
Fatigue Crack Velocity (m/cycle) 3.98x10 -15 ? K 70.3

Biocompatibility Tests and Results

Tests Result
Cytotoxicity L-929 Membrane Elution non-cytotoxic
Sensitization ISO Kligman 0% sensitization
Grade I sensitization rate not significant
Irritation Saline CSO negligible irritant
Acute Systemic Toxicity Saline CSO negative
Rabbit Pyrogen non-pyrogenic
USP Physical / Chemical Screening Tests passes USP standards
Mutagenicity Ames non-mutagenic
Hemolysis Direct Contact Rabbit Blood non-hemolytic
Complement Activation non-activating