PYROID® Pyrolytic Graphite PYROID® pyrolytic graphite (PG) is a specialized, "five-nine" purity, chemical vapor deposition (CVD), carbon product grown atom-by-atom with unique thermal, electrical and chemical properties including superior EMI performance. These materials have applications where extreme temperature up to 6000°F (3300°C) and corrosive environments exist, conducting heat across its (a-b) planar surface like copper and insulating like ceramics in the (c) thickness direction. As a result of our proprietary finishing process we achieve extremely low particulates and chemical resistance to fluorine-based gases that provide solutions to problems in plasma and semi-conductor etching systems. In addition, PG has been determined to be highly diamagnetic, conducive to enhanced imaging process for medical applications. The Pyrogenics Group provides parts and CNC machining, of diameters up to 18 in. (46 cm) and thickness up to 1 in. (2.5 cm). We supply PG in custom free standing as deposited shapes, having diameters up to 18 in. (46 cm) and varying wall thickness. Shapes can be manufactured such as cylindrical tubes, spherical domes, rods, plates, cones, and other intricate geometries. We are also the leading supplier of a special grade of freestanding PYROID® pyrolytic graphite films (2-75µm thickness) for use in high energy and radiation projects. With its unique thermal and electrical characteristics. PYROID® pyrolytic graphite is used by industries facing problem applications resulting from excessively high temperature, stress, corrosion, and friction, requiring a lightweight material solution.
Listed below is a general description of the processing and a summary of the key properties of pyrolytic graphite. The summary also lists important parameters of the product as it pertains to applications for thermal management.
- PYROID® pyrolytic graphite is markedly different from polycrystalline graphite and is in a specialty category. The absence of granular components and the unique structures of CVD deposited PG, yields components that achieve dropout rates at or below 10 per wafer—far below commercial graphite, and approaching that of silicon. In addition to having the lowest erosion material rate known, the size of the particulates generated is <0.1 µm and dropout distribution is uniform.
- The low ion sputtering rate in plasma applications results in enhanced lifetime, approaching several hundred hours in RF driven plasma devices, and is therefore, economically beneficial providing total cost solutions and enhanced productivity. PG is used widely in ion and rail gun applications due to its combination of high conductivity (in the a-b plane) and the very low sputtering rate offered by carbon in general. According to Ion Tech, PG offers the lowest sputtering erosion rate of any material used to construct ion grids.
- Exceptionally low metallic impurities (typical GDMs data avaiable upon request.)
- PG performs well at high temperatures and is stable up to 2200°C.
- PG approaches carbon’s theoretical density of 2.25 g/cc, and hence is essentially non-porous resulting in no outgassing of contaminants and is very stable in the more chemically active etching plasma applications, employing chlorofluro carbons and nitrogen trifluoride, that attack silicon.
- PG has excellent thermal conductivity, approaching copper in the a-b direction, whereas it acts almost as a ceramic on the 'c' direction. In an annealed PYROID® HT state, the thermal conduction properties increase up to four to eight times that of copper and aluminum, respectively (thermal conductivity as high as 1700 W/m°K). We are able to selectively bond the planes through special fixturing to take maximum advantage of its directional conductivity. In this regard it is an excellent material in special thermal management applications, including lids and heat sinks.
MINTEQ® supplies PG in flat machined pieces as required by the customer or fully machined parts (such as etching cathodes or grids) from customer specification or drawing. We have a CNC equipped machine shop and access to laser machining to fabricate complex shapes, critical dimensions and hole patterns in grids. We also offer a special surface treatment process after parts are machined to virtually eliminate particulate debris from the parts.