OnXLTI Contract Manufacturing product group - On-X® Carbon...pure isotropic pyrolytic carbon
OnXLTI company information
prosthetic heart valves
OnXLTI Cardiac Surgery product group
OnXLTI Contract Manufacturing product group
On-X Carbon Properties

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. (formerly MCRI). 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