Cordierite ceramic

Zeolites have also been used as raw materials for ceramic compositions relevant to the electronic industry. Bedard et al. reported the high-temperature processing of zeolite B (P) to form cordierite ceramic compositions [90]. 

Filio J.M., Sugiyama K., Kassi N. et. al. Effect of dry mixed grinding of talk, kaolinite and gibbsite on preparation of cordierite ceramics, J. Chem. Ing. Japan 1994 26 565-69. 

Table 8 MOR Data for Cordierite Ceramic Diesel Filters with 100/17 Cell Structure...

Cordierite, 2 MgO. 2 AI2O3. 5 Si02, is a compound with an extraordinarily low expansion coefficient. The content of this phase is responsible for thermal expansion of cordierite ceramics and for its resistance to thermal shocks. Linear thermal expansion coefficient of about 15 x 10 (20-300 °C) is attainable. However, difficulties are again encountered on firing, because of the large amounts of melt formed at the liquidus temperature. A difference of only several degrees may have the result that a small fired object contains both porous (insufficiently fired) as well as fused (excessively fired) zones. 

Sintered cordierite ceramics are used in the manufacture of electrotechnical components when resistance to thermal shock is required. The porous material is used for producing heating plates, carriers of heating coils, etc. 

Ceramics with a wide sintering interval include, for instance, porcelain for which temperature variations within limits of about 20 ""C have little effect on the final properties. In contrast, for example, with cordierite ceramics a change in temperature of several degrees may damage the ware seriously as a result of excessive melt formation. 

The successful performance of cordierite ceramic converter system over the past 19 years in a myriad of applications - automotive, light duty vehicles and trucks - has amply demonstrated its suitability as emissions treatment device [5]. Furthermore, new developments in the area of ceramic converter systems have helped extend their applicability to small engines, both two-stroke, used in motorcycles [6-8]. In addition to design flexibility, the ceramic converter offers higher offers higher use temperature, improved heath retention and lower system cost. 

Suzuki, H., Ota, K., and Saito, H., Preparation of cordierite ceramics from metal alkoxides (Part II). Sintering, Yogyo-kyokai-shi, 95(2), 170 (1987). 

The approximate phase diagram of a more complex system, Mg0-Al203-Si02, is drawn in Figure 4.22. Ceramic bodies are rarely pure phases, and cordierite ceramics, for example, have compositions over a region around the composition of cordiaite itself, as shown by the right-hand shaded area. In addition, the composition of some of these phases is... 

According to Figure 4.22, what phases are present in steatite ceramics and cordierite ceramics [Note answer is not provided at the end of this book.]... 

Extrusion is also used to produce the alumina shells for sodium vapor lamps and the honeycomb-shaped catalyst supports for automotive emission-control devices (see Chapter 37). The catalyst supports are designed to give a high surface area and can consist of hundreds of open cells per square centimeter with wall thicknesses <100 pna. To produce these shapes, cordierite ceramic powder is mixed with a hydraulic-setting polyurethane resin. The mix is extruded into a water bath at a rate that matches the rate of cure of the polyurethane (about 2mm/s). It is then fired to produce the final ceramic. 

Kurama S, Kurama H (2008) The reaction kinetics of rice husk based cordierite ceramics. Ceram Int 34 269-272... 

Catalytic Converter. A device to remove noxious components from the hot exhaust gases of diesel and petrol engines, by passing them over a suitable catalyst to promote their breakdown. Cordierite ceramic honeycombs are the usual catalyst carriers. 

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