NON-DESTRUCTIVETHERMAL DAMAGE CHARACTERIZATION OF CORDIERITE-MULLITEREFRACTORIES

Refractory materials containing cordierite (2mgo·2ai2o3.5sio2) and mullite (3ai2o3.2sio2) are used as support in furnaces, because oftheir low thermal expansion properties which confer them a very good ability to thermal shock resistance. composed 0.( tvt·o phases presenting vet)' different cte (1.5-3 x 10^-6 .(0 1' cordierite and 4-6* i0^-6 k-1 for mullite) , these materials can develop damage during thermal cycling due to internal stresses. the resulting network ofmicrocracks is well known to improved thermal shock resistance of materiais, since it usually involves a significant decrease in their elastic properties. this paper is devoted to the characterisation ofthe damage generated by this cte mismatch, thanks to the application ofa specific ultrasonic device at high temperature