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SHS technology to save energy, fast synthesis speed and high purity of the product characteristics, are widely used in metal - ceramic composites . However, this technique synthetic composites generally contain a higher porosity ( 20% -50% ) , and can not be used directly as a structural material . Therefore , the integration of SHS - densification has been a focus for researchers . In addition, due to the thermodynamic limit of the SHS reaction , this technique is only suitable for highly exothermic reaction system . Therefore , how to limit induced by SHS reaction thermodynamics of the reaction system from the spread of burn, in order to further enhance the range of technical synthetic material , is also a development direction SHS technology . TiO 2 -C-Al reaction system for the study, designed to use liquid aluminum formed in the SHS process of pore filling and welding effect , to further improve the compactness of the synthetic composites . The results show that , with the system over more than the increase of Al content x value , Composites improved in density . However , when the system over the remainder of aluminum content x gt ; 10 mol SHS reaction , the system is difficult to occur . For this reason, using the combined effect of the electric field induced higher than the amount of aluminum ( x = 14 mol ) the TiO 2 < / sub > - C- Al system self-propagating combustion , and direct synthesis of compactness up to 92.5% of Al 2 O 3 -TiC-Al composite materials. In addition, the paper analyzes the SHS reaction thermodynamics in the electric field , the corresponding mathematical model ; electric field intensity of the reaction system of the TiO 2 -C-Al SHS process and the organizational structure of the synthetic materials and to explore Al 2 O 3 -TiC-Al composite structure formation process . The results showed that : the Joule heat effect of the electric field to improve the system 's initial reaction temperature , when the applied electric field strength E ≥ 7.5 V / cm , the electric field can break the thermodynamic limit of the SHS reaction ; Moreover, with the electric field intensity increases , the system SHS reaction shorten the required ignition timing , the combustion temperature and the combustion wave spread faster synthesis of Al 2 < / sub > O 3 < / sub > and TiC grain size decreases, the composite densification improves . Therefore, the electric field -SHS technology provides a simple way for the direct preparation of dense metal - ceramic composites .
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