Research On The Preparation And Properties Of Honeycomb Ceramics

Honeycomb ceramics are used as substrates for automotive exhaust catalysts and ozone abatement catalysts. They are also can be used for heat exchange and molten metal filtering. Now the cordierite are more popular in making honeycomb ceramics than the mullite. While the cordierite has its disadvantages such as the narrow burned temperature, and it can be only used on a lower temperature in the alkale resistance environment. The cordierite has a lower thermal conductivity which will increase the melting point and make the regeneration more difficultly. The mullite has high-temperature stability, resistance against thermal strain, corrosion stability and a low price to fulfill the requirements on filtration, regeneration and application in a system. The SiC has a relatively high thermal conductivity. This thesis described the performance of the mullite-SiC based honeycomb ceramics, studied mainly the process for manufacturing mullite-SiC honeycomb ceramics with C powder as porosity aid. Green body strength, fired strength and porosity were tested to decide the best ingredient. The microsturcture of ceramics was test by SEM method. The results show that as follow.1,Mullite-SiC are chosen as the main materials with C powder as porosity aid to make the honeycomb ceramics. The result shows that it can make the porosity ceramics and cost less.2,The additive has different effect on the process of the honeycomb ceramics. The reasonable compose of the additive is that MC as achesive, glycerin as plasticizer and tung oil as lube.3,Forming process was: The vacuum was 0.09MPa, and kept 2min when the pressure was 5MPa. The highest forming pressure was 20MPa.4,The honeycomb ceramics were dried frist in nature for 3 to 5 hours and then in the oven. The drying process: 50℃1h,70℃1h,100℃1.5h.5,The mullite based honeycomb ceramic was fired at the temperature of 1200℃and was kept at 1200℃for 2 hours.6,The results show that the porosity was 56.4% when C powder was 10%; 60.5% when C powder was 15%, and 56.5% when C powder was 20%. It is suggested that the honeycomb ceramic's porosity will be higher when the C powder is 15wt%.