Pyrograf I

High Resolution SEM of Pyrograf I Fibers

Pyrograf-I is a vapor-grown carbon fiber (VGCF) produced via a fixed catalyst method.  Pyrograf-I fibers have a diameter range of 3-20 microns, and a length range of 1-10 cm.

VGCF has been studied worldwide by a number of investigators and has been described in the carbon literature for the last thirty years.  An excellent overview of research performed on VGCF and comparison to conventional carbon fibers is available in Graphite Fibers and Filaments.[1] A table of the physical properties of Pyrograf-I before and after heat treatment is shown below.   After heat treatment Pyrograf-I provides exceptional thermal conductivity.

Pyrograf I provides exceptional thermal conductivity, approaching the theoretical value of graphite, making it ideally suited to the most  demanding thermal management applications.

 

Aluminum Heat Spreader Composite Heat Spreader

 

Pyrograf-I Properties

Property As Grown Heat Treated Units
Fiber Diameter 3 to 20 3 to 20 microns
Density 1.8 2.1 g/cm3
Tensile Strength 2.7 7.0 GPa
Tensile Modulus 400 600 GPa
Coefficient of Thermal Expansion -1.0 ppm/oC
Electrical Resistivity 1000 55 microohm-cm
Thermal Conductivity 20 1950 W/m-K

 


Low Density

The key attributes of  Pyrograf-I composites are not only their superior thermal conductivity, but their low density for a very high mass specific thermal conductivity.  This metric is especially critical for weight sensitive applications such as aircraft and satellites.

Production Method

VGCF is produced in a catalytic process from hydrocarbon gas.  The purity of the carbon source and the mechanics of growth result in a highly graphitic fiber with physical properties approaching those of single-crystal graphite.  The enhanced mechanical properties may enable engineered composites to be considered where previously only structural metals or advanced composites could be contemplated.

Applications

Owing to the very high thermal conductivity of Pyrograf-I, the material is solely used for thermal management applications.  Whether the material is incorporated into carbon-carbon composites, metal matrix composites, or polymer composites, Pyrograf-I can significantly enhance the thermal conductivity of the composite system it is used in.  Applications for Pyograf-I include heat-spreaders for consumer electronics, aircraft, and aerospace platforms, as well as integrated gate bipolar transistors for automobiles.

 

Contact Patrick D. Lake to discuss Pyrograf-I or your thermal management needs.

Mr. Lake is a Chemical Engineer with over 15 years experience in the growth of vapor grown carbon fibers and carbon nanofibers, and the development of downstream products using these materials. Mr. Lake is also experienced with development of high thermal conductivity composites including carbon-carbon composites and increasing thermal conductivity in traditional carbon fiber reinforced polymer composites.

 

 

 


[1].  M.S. Dresselhaus, G. Dresselhaus, K. Sugihara, I.L. Spain, H.A. Goldberg, Graphite Fibers and Filaments,  Springer-Verlag, New York (1988).