Forming and sintering of in situ alumina composite with hydraulic inorganic binder

Two types of barium aluminate binders were prepared by heat treatment of ba rium aluminate precursors, synthesized by using solution processes, at low temperatures (T < 500 degrees C). One was barium monoaluminate (BaAl2O4), a nd the other was barium aluminate binder (BAH binder) composed of amorphous phase, barium aluminate monohydrate (BaAl2O4. H2O), and BaAl2O4. The setti ng time of the BAH binder was controlled by adjusting the heat-treatment te mperature of the BAH binder precursor. The addition of the synthesized BaAl 2O4 powders to Al2O3 powders improved the bending strength of Al2O3 matrix green bodies. The synthesized BaAl2O4 powders led to the in situ forming of barium hexaaluminate (BaO . xAl(2)O(3), x = 6.9: BA6) platelets in the mat rix by reacting with Al2O3 during sintering, The formed BA6 platelets inhib ited the grain growth of the matrix Al2O3 grains.