On-X Carbon Overview
- On-X carbon is a pure form of isotropic pyrolytic carbon utilizing patented processes
- It does not require silicon alloying to ensure wear resistance found in most other available forms of pyrolytic carbon
- It is a structural carbon coating that is most often deposited on a high density, high purity graphite pre-form
- Other substrate pre-forms can be used
- Components of solid On-X carbon can be produced
- Thickness of the deposited carbon depends on the design requirements of the product
- The surface can be polished to a high gloss where articulation or thromboresistance is required
- Alternatively, the surface can also be left in an as deposited state providing some surface topography for bone and or tissue on-growth
What is Pyrolytic Carbon (PyC)?
- Pyrolytic carbon is an isotropic turbostratic form of carbon.
- The crystalline structure of pyrolytic carbon has a distorted lattice structure with random unassociated carbon atoms (ref. a) unlike, as an example, graphite (ref. b).
- This structure provides it with isotropic properties (similar in all directions)
- It is formed by pyrolysis of a hydrocarbon gas creating random crystallization
- It exhibits excellent stability, strength, wear resistance, fatigue resistance and biocompatibility
How is Pyrolytic Carbon (PyC) Produced?
- PyC is generally deposited as a structural coating over a substrate pre-form
- Alternately, for some geometries solid PyC can be generated
- It is usually formed in a fluidized bed furnace
- The bed consists of small ceramic particles and parts to be coated
- A levitating gas creates required random motion of parts within the bed
- Heating elements raise furnace temperature to 1200° -1400°C
- An introduced hydrocarbon gas undergoes decomposition at these temperatures creating free carbon that recrystallizes on whatever surface it comes in contact with first