TaxTi1-xC and TaxTi1-xCyN1-y whiskers have been synthesised via a carbothermal vapour-liquid-solid (VLS) growth mechanism in the temperature region 1250-1400 degrees C, in argon and nitrogen atmospheres, respectively. The starring materials consisted of Ta2O5, TiO2, C, Ni and NaCl. Carbon was added to reduce the oxides, and nickel to catalyse the whisker growth. NaCl was used as a source of Cl for vapour phase transportation of Ta-oxochlorides and Ti-chlorines to the catalyst. The yield of whiskers was about 80 vol%, with a length of 10-30 mu m and a diameter varying fi om about 0.25 mu m for TaC to about 0.55 mu m for TiC. The whiskers were straight and had smooth surfaces. TEM studies show ed that they were monocrystalline. The average x-value of the formed whiskers could be controlled by varying the weighed-in ratio of Ta2O5 to TiO2 and the synthesis temperature. The maximum nitrogen content decreased with increasing x value in TaxTi1-xCyN1-y. The residual oxygen content in the whiskers decreased,with increasing synthesis temperature and increasing x-value. (C) 1998 Elsevier Science Limited. All rights reserved.
