چكيده به لاتين
MAX phases are layered ternary carbides and nitrides with general formula: M n + 1 A X n , where "M" is an early transition metal, "A" is an A-group (mostly groups 13 and 14) element, and "X" is C and/or N. This materials have aroused researcher’s more and more interest due to their unique combination of properties of both metals and ceramics, such as high melting point, low density, excellent high temperature mechanical properties, thermal stability, excellent thermal shock resistance, good electrical and thermal conductivity and machinability. As a representive of MAX phases, Titanium Silicon Carbide (Ti3SiC2) has attracted much attention owning because of its special properties. selection of the synthesis route and processing parameters are of vital importance in the actual application of the powder. Therefore, it is necessary to follow methods using lower synthesis temperature and time. The aim of this research was to produce Ti3SiC2 from elemental powders and to investigate process parameters with respect to optimized Ti3SiC2 yield by use of two sources of carbon (carbon black and graphite) by low temperature molten salt synthesis method. Through the work performed it has been found that Ti3SiC2 may be produced in small quantities by use of barbon black in raw materials (3 Ti / 1.2 Si / 2 CB / 0.5 Al) because of formation of large amount of TiC due to high chemical activity of this carbon and formation of TiSi2 as silicide phase. However, Ti3SiC2 were synthesized in relatively large quantities (85/82 wt%) by use of graphite in raw materials because of formation of TiC and Ti5Si3 as intermediate phases. Ti5Si3 is found to play a key role in the formation of Ti3SiC2 from elemental powders. The optimum experimental parameters for the synthesis of Ti3SiC2 were determined as a Ti / Si / Cg / Al molar ratio of 3/1.2 / 2 / 0.5 and using firing of the mixture of NaCl and KCl as the flux. The suitable salt / powders weight ratio and pre-press were 1:1 and 150 MPa, respectively. The synthetic temperature of Ti3SiC2 by molten salt synthesis method was 1200 °C, which was about 150 – 200 °C lower than that reported by other methods.
