Self-Propagating High-Temperature Synthesis SHS

With the proper conditions, highly exothermic reactions, once initiated, will spread as a combustion wave throughout the reactants mix-ture. These reactions, originally developed in Russia, are used to produce powders of almost all the refractory carbides and nitrides. 

The adiabatic temperature iJad) of the compound, i.e., the processing temperature at which no heat enters or leaves the system, can be used as an indication of the temperature at the combustion front. As shown in Table 14.4, this temperature can be very high, particularly with the refractory nitrides. 

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TABLE 9.5 Compounds Produced by Self-Propagating, High-Temperature Synthesis (SHS)a... 

In addition to conventional sintering, reactive powder processing, also called combustion synthesis or self-propagating high-temperature synthesis (SHS), can be used if the target compounds can be synthezised from the starting powder mixture (Stangle and Miyamoto, 1995). This process comprises a rapid and exothermic chemical reaction to simultaneously synthesize some or all of the constituent phases in the FGM and density the component. 

Self-Propagating High-Temperature Synthesis (SHS) Conventional methods of synthesizing materials via solid reactions involve... 

Four different routes were employed for the synthesis of iron-oxide-based redox water-sphtting materials Solid-State Synthesis (SSS), Self-Propagating High-Temperature Synthesis (SHS), Gel Combustion (GC) and Aerosol Spray Pyrolysis (ASP) [8]. These synthesis methods were chosen with the rationale to exploit particular characteristics of each one for the synthesis of products with tunable oxygen vacancies concentration. The synthesis details have been reported previously [8], therefore only the general reaction concepts are reported below, where A and B denote the bivalent dopant metals Ni, Mn or Zn. 

Combustion synthesis (CS) can occur by two modes self-propagating high-temperature synthesis (SHS) and volume combustion synthesis (VCS). A schematic diagram of these modes is shown in Fig. 1. In both cases, reactants may be pressed into a pellet, typically cylindrical in shape. The samples are then heated by an external source (e.g., tungsten coil, laser) either locally (SHS) or uniformly (VCS) to initiate an exothermic reaction. 

Dutta, A., Self-propagating high-temperature synthesis (SHS)-cum-superplastic forging of FesAl-Nb alloy. Int. J. SHS, 4,309 (1995). 

Padyukov, K. L., Levashov, E. A., Borovinskaya, I. R, and Kost, A. G., Specific features of the behavior of synthetic diamond in a self-propagating high-temperature synthesis (SHS) combustion wave. J. Eng. Phys. Thermophys., 63,1107 (1992b). 

In the second phase of the development, the ability of property estimation of the network is examined with the data samples which are measured from the experimental process but never used in the training session. Based on the experimental data which were available for the trial, we trained and tested the ANN network to predict densities of FGM. Table 1 shows the comparison of measured and the network estimated densities of as-synthesized TiB2-Cu FGM using the Self-propagating High-temperature Synthesis (SHS) technique. The result indicates that the ANN network can give quite good estimations to the FGM properties. 

In this work, we used oxynitride block catalysts produced by self-propagating high-temperature synthesis (SHS) [3,4] for purification of the gaseous mixtures modeling exhaust gases from carbon monoxide, hydrocarbons,and nitrogen oxide. 

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