Synthesis of nanocrystalline titanium carbide by spark erosion
Interest in nanocrystaJline ceramic powders is due to their attractive processing and mechanical properties. The disadvantages of conventional ceramics, such as large internal flaws, negligible ductility, hightemperature processing, can possibly be eliminated or minimized by starting with finegrained powders. A previous study on the sinterability of nanocrystalline ceramic powders showed that high densities can be achieved at lower temperatures, both with and without the’ application of pressure [ 11. In addition, it is remarkable that superplastic behavior has been reported in nanocrystalline ceramics at room temperature [2]. One of the novel methods for nrenaring nanocrvstalline ceramic powders is reactive spark erosion [3-51. An important feature of this method is the-capability to synthesize new materials by reacting the eroded particles with the dielectric liguid. This technique utilizes two metal or conducting electrodes sparked in a suitable dielectric liquid that reacts with the pa&les to produce the desired ceramic powders. The high temperature provided by the spark results in vaporization of the electrodes and the surrounding dielectric liquid; the reaction products formed between the various vapor species are quenched in the liquid and produce spherical particles. The aim of the present note is to report on the titanium carbide particle formation in a carbonic dielectric liquid (pentane) with titanium electrodes and charges. The nanocrystalline titanium carbide was produced in a wide range of particle size distribution and in the form of single phase spheres.
A New Reduction-Carburization Route to Nanocrystalline TiC
Nanocrystalline TiC was synthesized through a new reduction-carburization route by using metallic Na as the reductant, and tetrachlorotitanium (TiCl4) and carbon as Ti and C sources at 650 °C. The present route allowed for the formation of nanocrystalline TiC with fine particle sizes, narrow size distribution (8-12 nm). A possible formation mechanism for nanocrystalline TiC was proposed.
Comparative studies of ecm, edm and ecam
Abstract The characteristics of electrochemical and electrodischarge machining are compared with electrochemical arc machining, a process which relies on electrical discharge in electrolytes to effect metal removal. Since little is known about the nature of this process, investigations of sparks in dielectrics and electrolytes are reviewed. Some relevant applications of edm and ecm are then discussed, and comparisons drawn with the new process