INFLUENCE OF THE CABORES CONTENT ON THE STRENGTH OF CARBON BONDED ALUMINA OBTAINED BY MEANS OF SMALL PUNCH TEST

The material investigated is used for the production of open cell foam filters. These filters are used for the filtration of metal melts. All material compositions contain 30wi% residual carbon after coking. The Cabores P content is varied from 10wt% to 20wt%. The mechanical tests were carried out by means of the Small Punch Test (SPT). The main advantage of this test method is the small amount of material necessary for the tests. The thickness of the samples is in the same range as the thickness of the struts of the filters. The specimens are exposed to a biaxial state of stress. This test setup therefore provides conditions which are close to the in-service conditions of a filter during casting. The specimens for the tests are manufactured by a slip casting process route. A comparison to specimens where the material is uniaxial pressed showed that it is essential to keep the specimen production route close to the way of the filter production. The results showed that the strength of the carbon bonded alumina is increasing with an increasing Cabores content.