EFFECT OF Al_2O_3 ON THE FORMATION OF Ba_2Ti_9O_(20)
掺杂 Al_2O_3对 Ba_2Ti_9O_(20)相形成的影响

An investigation was made of the effect of Al_2O_3 compound on the formation ofBa_2Ti_9O_(20)phase in the solid state reactions.The formation of Ba_2Ti_9O_(20)crystal,which is diffi-cult in the BaO-TiO_2 binary system because of stress arising along the crystal-sturcture layerscaused by the structural factor,can be eased by the addition of a little Al_2O_3 into the binary re-action system.When Al_2O_3 participates in the reaction,BaAl_2Ti_6O_(16)crystal is formed and ex-ists in the way of inter-growth with the crystallizing Ba_2Ti_9O_(20)crystal.The intergrowthremarkebly decreases the stress arising along the crystal-structured layers of the crystallizingBa_2Ti_9O_(20)and reduces the height of potential energy barrier of its crystallization,resulting in itseasy formation in the reactions.