Effect of ceramic binders on microwave dielectric loss of alumina

Several binders have been evaluated to determine their effect on high frequ ency dielectric loss. Alumina ceramics have been powder pressed with differ ent binder levels, sintered. and then the dielectric loss (tan delta = Q(-1 )) has been measured at approximately 9.5 GHz. The quality factor Q was det ermined and significant differences were observed between samples made with different binders. The differences are caused by the different levels of r esidual porosity left by the different binders. In addition, differences in levels of impurities in the binders may also influence Q. Selected samples were measured fbr green body strength as a function of binder content.