Thermal stability of nanometric TiC-carbon composites: effects of carbon allotropes and Zr milling impurities

J.P Ramos,T Stora,A.M.R Senos,P Bowen

doi:10.1016/j.jeurceramsoc.2018.07.002

Abstract

In the ISOL (Isotope Separator OnLine) method a target at high temperatures (up to 2300 °C), is bombarded with high energy protons in order to produce isotopes through nuclear reactions which are simultaneously extracted from the target, ionized and delivered to physics experiments. Due to the enhanced isotope release properties of nanosized porous materials, titanium carbide-carbon porous nanocomposites have been developed at CERN and tested up to 1500 °C. In the interest of the ISOL application, in this study we extended the range of temperatures up to 1800 °C, to test the sintering hindering capabilities of different carbon allotropes. Carbon black was the most effective with the smallest TiC crystallite size: <80 nm at 1800 °C. Additionally, using thermodynamic modelling, ex-situ X-ray powder diffraction and in-situ gas phase analysis, we show that there are interesting additional phase and lattice parameter changes due to the ZrO2 impurities from the attrition milling.

Highlights

Radioactive ion beams are used all over the world for nuclear, atomic, solid state and bio-physics studies
The ISOL target materials can benefit from the smallest grain size and high porosity stable at the highest possible temperature
The value of 51 nm obtained for TiC XS is consistent with scanning electron microscope (SEM) measured particles (64 ± 29 nm [23]) and with particle size calculated from Specific surface area (SSA) (48 nm – Table A.2.1 in supplementary materials)

Summary

Introduction

Radioactive ion beams are used all over the world for nuclear, atomic, solid state and bio-physics studies. ISOLDE uses the ISOL (Isotope Separator OnLine) method to produce radioactive isotopes where high energy particles, in this case protons at 1.4 GeV, are used to bombard a target to induce nuclear reactions which transmute a fraction of the target material atoms into different isotope elements of a lower mass number [2]. Such isotopes are trapped in the bulk of the target material and have to diffuse to the surface, evaporate and diffuse through the material porosity to a transfer line ( called effusion) connected to an ion source. The separated beam is conducted to the experimental setup where it will be used for physics research

Methods

Results

Conclusion