Particle size, self-propagating synthesis

Solid-phase reactions are usually activated by high-temperature treatment [1-4]. However, the practical efficiency of this process is rather low since the diffusion rate through a product layer is small, no tight contacts between the particles of components are provided, a particle size distribution is non-uniform, etc. Therefore, the search for new methods of performance of solid-phase reactions is carried out. Some new methods are successfully used for these purposes. These methods include, for example, self-propagating high-temperature synthesis [5], shock waves [6,7], mechanical activation of mixtures in grinding apparatus [8-15]. The latter method becomes more widely used at present due to its relative simplicity and availability. 

Mechanically induced self-propagating reaction — ignition of self-propagating high-temperature synthesis (SHS) (see) by means of mechanochemical treatment, preceded with an activation period, that is, ignition time, during which particle and crystallite size reduction, mixing and defect formation take place. 

In the present study, the following self-propagating high-temperature synthesis was adapted to produce alumina/ SiC nanometer-sized particles composite,... 

ZrB derived from self-propagating high temperature synthesis (SHS) with a particle size of 2.8pm attained a RD of -94% when sintered at 1800°C for 60 min in flowing argon (Mishra et al., 2002). A small amount of ZrO is observed during microstructural analysis, bnt it is concluded that the densification is activated by Fe... 

---