Synthesis of Carbon Nanotubes on Zirconium Alloys Surface

Abstract

The radiation-stimulated structural phase transformations can significantly affect the processes influencing on the structural materials operation under radiation and high temperatures conditions. These processes lower reliability and service life of shells and covers thus reducing the times of safe operation of nuclear reactors. Therefore the search for the way and technologies directed to the increase in reliability and durability of fuel element (tvels) shells and thermal converter covers is a special issue of the present day. The purpose of the present paper is to give the description of the performed series of experiments on carbidization of the zirconium substrate surface. Such carbidization has been conducted through the carbon nanostructures dissolution in the matrix volume under various conditions of heat treatment. Metallic and nonmetallic catalysts have been used to synthesize carbon nanostructures on the zirconium alloys surfaces. The surface of test specimens of thermal fuel elements (tvels) has been subjected to grinding and also to the electrolytic polishing in acid-water solution for taking the strain hardening. Carbon nanostructures have been synthesized on the substrate surfaces by the method of acetylene pyrolysis. Nickel nanoparticles deposited on the substrate by cladding have been used as a metallic catalyst. Synthesis of carbon nanostructures on such catalysts allows the formation of uniform layer of carbon nanotubes on the sample surface. The microhardness has been measured for the synthesized specimens with nanotubes on the zirconium substrate cladded with nickel and compared with initial samples. The study has revealed that the microhardness of treated specimens increases, resulting in the hardening of tvel covers by carbidization and in doing so authors have found a way to the rise of reliability and durability of tvel shells and thermal converter covers hardenable by heat-treatment.