SINTERING BEHAVIOR OF COMPACTS MADE FROM TELEVISION TUBE GLASSES

The sintering behaviour of glass powders obtained from discarded telev ision tubes was studied. A screen glass and a mixture of screen and Pb containing cone glass were considered. Cylindrical powder compacts we re prepared by uniaxial pressing and the densification behaviour durin g sintering was investigated in isothermal conditions using a heating microscope. At 650 degrees C the samples of both compositions became n early fully dense in less than 1 h. Both samples showed a similar vary ing shrinkage anisotropy during densification. At the earlier stages o f sintering the radial shrinkage was higher than the axial shrinkage. This behaviour was reversed at the later sintering stages after the co mpacts had reached a relative density of 89%. This anisotropic densifi cation behaviour can be explained qualitatively by considering the mic rostructural arrangement modifications that occur during the sintering process. Experimental values for the shrinkage behaviour in the radia l direction were in very good agreement with the theoretical predictio n of the stereology based model equation of Exner & Giess.