Boron coatings on graphite for fusion reactor applications

This study is an experimental investigation of boron coatings on graphite and the preliminary determination of some of their physical and nuclear related properties. The boron was obtained by the decomposition of diborane in argon at 5000C and one atm. Adhesion to the graphite (POCO AXF-5Q) was good if a slightly abraded surface was provided. The boron was pseudo-amorphous, had high purity with no visually observable porosity and the fractured surface showed no growth features. It was very hard (VHN25 = 2400 kg/mm2) and had good resistance to hydrogen ion erosion and arcing. It may, therefore, be a suitable candidate for first wall and limiter coatings in tokamak fusion reactors