APPLICATIONS OF BAKED AND GRAPHITIZED CARBON

Giaphite with its exceptional strength and thermal stabiUty at high temperatures is a prime candidate material for many aerospace and nuclear appHcations. Its properties, through process modifications, are tailorable to meet an array of design criteria for survival under extremely harsh environmental operations. 

Aerospace and nuclear reactor appHcations of graphite demand high reHabiHty and reproducibiHty of properties, physical integrity of product, and product uniformity. The manufacturing processes require significant additional quaHty assurance steps that result in high cost. 

The erosion of graphite in nozzle appHcations is a result of both chemical and mechanical factors. Changes in temperature, pressure, or fuel-oxidizing ratio markedly affect erosion rates. Graphite properties affecting its resistance to erosion include density, porosity, and pore size distribution 

Graphite is chosen for use in nuclear reactors because it is the most readily available material with good moderating properties and a low neutron capture cross section. Other features that make its use widespread are its low cost, stabiHty at elevated temperatures in atmospheres free of oxygen and water vapor, good heat transfer characteristics, good mechanical and stmctural properties, and exceUent machinabUity. 

Neutron economy in graphite occurs because pure graphite has a neutron capture cross section of only 0.0032 0.002 x lO cm. Taking into account the density of reactor grade graphite (bulk density 1.71 g/cm ), the bulk neutron absorption coefficient is 0.0003/cm. Thus a slow neutron may travel 32 m in graphite without capture. 

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CARBON - CARBON AND ARTIFICIALGRAPHITE - APPLICATIONS OF BAKED AND GRAPHITIZED CARBON] (Vol 4)... 

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