The role of sintering additives on synthesis of cermets by auto-combustion

• Published in: Powder technology 2010-01, Vol.197 (3), p.303-308
• Main Authors: Ali-Rachedi, Mahieddine, Ramdane, Wisseme, Vrel, Dominique, Benaldjia, Abdelaziz, Langlois, Patrick, Guerioune, Mohamed
• Format: Article
• Language: English
• Subjects: Aluminothermic reaction; Cermets; Diffraction; Doping; Engineering Sciences; Explosions; Materials; Nickel; Self-propagating synthesis; SHS; Sintering (powder metallurgy); Sintering additives; Synthesis; TiC–Ni–Al 2O 3 system; Titanium carbide
• ISSN: 0032-5910; 1873-328X
• DOI: 10.1016/j.powtec.2009.10.009

The purpose of this work is to decrease or eliminate porosities in SHS products with sintering additives. The Ti–C system has been synthesized for its advantages for refractory, abrasive and structural applications. We attempted to densify TiC by using Nickel addition; this metal is introduced through a secondary reaction 3NiO + 2Al. This mixture reacts exothermically and the heat is released according to 3NiO + 2Al → Al 2O 3 + 3Ni. So, the introduction of the Al 2O 3 diluent with the starting reactants is necessary because of the explosive character of the thermite reaction. Thus, doping method is finally used to fabricate materials by SHS method (self-propagating high temperature synthesis). Final products were analysed by X-ray diffraction and scanning electron microscopy. The purpose of this work is to decrease or eliminate porosities in SHS products with sintering additives. The Ti–C system has been synthesized for its advantages for refractory, abrasive and structural applications. We attempted to densify TiC by using Nickel addition; this metal is introduced through a secondary reaction 3NiO + 2Al. This mixture reacts exothermically and the heat is released according to 3NiO + 2Al → Al 2O 3 + 3Ni. So, the introduction of the Al 2O 3 diluent with the starting reactants is necessary because of the explosive character of the thermite reaction. Thus, doping method is finally used to fabricate materials by SHS method (self-propagating high temperature synthesis). Final products were analysed by X-ray diffraction and scanning electron microscopy. [Display omitted]