J.M. Ramos-Fernández, University of Alicante (Spain); M. Martínez-Escandell (Sp), F. Rodríguez-
Reinoso, University of Alicante (Spain)
Carbon materials are good candidates for new applications in extreme environments. They offer many of the desirable requirements for plasma-facing materials: low atomic number, good thermo mechanical properties, high thermal conductivity, high melting temperature and low coefficient of thermal expansion. However, the properties of these C-based materials still need to be improved. The presence of other elements, as free elements or in chemical compounds (such as titanium, zirconium, vanadium, etc) has been used in order to improve the material properties. Heteroatom doped graphites can be obtained using mixtures of coke, binder and heteroatom carbide with high heteroatom dispersion and improved properties. The production of doped-carbon materials via co-pyrolysis of a carbon precursor with a heteroatom source soluble in the carbon precursor is a good alternative to produce doped self-sintering carbons with a homogeneous particle distribution. This material can be used to produce graphites without the need of using a binder. The heteroatom
precursor must be soluble in the carbon source (usually carbon or petroleum pitch) in order to achieve a good dispersion of the dopant. In our case, mixture of a petroleum residue with a Ti or Zr-organometallic compound (titanium butoxide or zirconium acetyl acetonate) has been pyrolysed to obtain a doped self-sintering carbon material with homogenous heteroatom distribution.
The presence of the heteroatom source affects to the pyrolysis behaviour of the mixture, causing changes in the microstructural ordering of the carbon obtained. The presence of the heteroatom causes an enhancement in the cristallinity of graphites obtained, which allows to increase properties such as electrical and thermal conductivity, reduce CTE, etc., without decreasing mechanical properties. The effect of synthesis parameters (heteroatom source, concentration, etc) on microstructure and properties of the self-sintering carbons and the final graphites is analysed.