چكيده به لاتين
SiC-TiC composite, especially in Nano-scale, has a wide range of properties including resistanc to corrosion, oxidation and thermal shock, also high fracture toughness, high hardness, and abrasion-resistant. So SiC-TiC composites have attracted researchers due to theis unique properties. However, high purity and nanosize processed of this composite is preferred in applications. Carbides synthesize is so hard and expensive rather than conventional methods. There are some methods for synthesizing of SiC-TiC composites such as carbothermic reduction of TiO2-SiO2, reaction of gas-phase laser-induced and so on. But some of these processes have been costly and needed high-temperature equipment; therefore some cost-efficient ways have been adevised for carbide production recently. The sol gel method is one of the suitable ways of preparing fine powder, fibres and films of metal oxide glasses and carbides. This process makes it possible to synthesize and produce different types of nanoparticle and providing condition for unique properties. The main aim of this project was to synthesize SiC-TiC nanoparticle by sol gel method using titania and silica sols. For preparation of the sols, Titanium tetra isopropoxide (TTIP), Tetra ethoxy silane (TEOS), isopropanol, ethanol, and sucrose were used. After completing hydrolysis and gel formation following by heat-treatment, the SiC-TiC nanoparticles were produced. Analysis methods such as FTIR, XRD, DTA/TG and SEM were used to characterize the samlpes. The effects of calcination atmosphere in Coke bed, Ar+25%H2 and pure Ar atmospheres on the product were investigated. In Coke bed and Ar+25%H2 atmosphere resulted oxide phases but in Ar atmosphere, the nanosized SiC-TiC composite powders were synthesized with different portions of SiC and TiC. The effect of temperature on the purity of the product was investigated using XRD and SEM analysis. By increasing temperature from 1450℃ to 1500℃, the amount of amorphous phase was reduced, and pure SiC-TiC composite powder was synthesized. The optimum conditions for synthesizing of nano-structured composite powder with the size of less than 100 nm was achieved in Ar atmosphere and 1500℃.
Keywords: Sol gel, Sucrose, SiC-TiC Composite.
