Oxidation Protection of Graphite by BN Coatings

Increasing the service life of different graphite parts at high temperatures is very important in many industrial applications. One way to achieve this objective is to produce oxidation protection coatings of boron nitride on graphite substrates. The chemical inertness and oxidation resistance of boron nitride has led researchers to consider this material as one of the best coatings to protect graphite against oxidation. Many aspects of obtaining nitride coatings on graphite substrates by forming a boron nitride layer in a heterophase process have been investigated. Oxidation tests performed on the coated graphite have revealed a high efficiency of boron nitride coating for graphite protection. As compared with that of uncoated specimens the oxidation resistance of BN-coated graphite substrates was 8 times higher at 750?C and 12 times higher at 1200?C. The studies have shown that boron nitride coatings can effectively protect carbon materials against oxidation and increase the service life of these materials at high temperatures.