h i m u r a C e n t r a l R e s e a r c h L a b o r a t o r y o f Sumitomo M e t a l Mlning C o . , L t d . Nakakokubun 3-18-5, I c h ikava-Shl. Ch i b a 272. J a p a n * P r e s e n t A d d r e s s D e p a r t m e n t of M e t a l l u r g y and M a t e r i a l s E n g i n e e r i n g , L e h i g h U n l v e r s l t y . B e t h l e h e m , PA 18015. U.S.A. Abstract An a p p l i c a t i o n o f a f a s t h e a t i n g p r o c e s s a t t a i n s a r e m a r k a b l y h i g h Q v a l u e of t h e p u r e BMT (Ba(Mg1/3Ta2,3)03) c e r a m i c s . Q v a l u e s t r o n g l y d e p e n d s on t h e o r d e r i n g of t h e B s i t e i o n s and t h e d e n s l t y of t h e c e r a m i c s b u t n o t on t h e g r a i n s i z e . I t is found t h a t t h e The maximum Q v a l u e i s o b t a i n e d f o r t h e h i g h d e n s i t y a n d h l g h o r d e r , which a t t a i n s more t h a n 35000 a t 10CHz. I . I n t r o d u c t i o n R e c e n t l y complex p e r o v r k i t e compounds v i t h the g e n e r a l f o r m u l a A

Dissolution and reaction of yttria-stabilized zirconia (YSZ) single crystals were investigated in various solutions at 600" to 780OC under 100 MPa. YSZ crystals were not corroded in pure H20 and neutral solutions such a LW, LEI, NaNOJ, KCl, KBr, K2S04, and Na2S04 even under severe conditions at 600°C, 100 MPa. They were, however, dissolved and reprecipitated in basic solutions such as NaF, K2COJ, KOH, NaOH, and LiOH with partial decompositon (destabilization) in the last three solutions. YSZ crystals were completely decomposed into m-Zr02 in acidic solutions of Li2S04, H2S04, and HCl, whereas they reacted with the solution and formed other compounds in KF', NH& and HJP04 solutions.

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Dielectric constant and the temperature coefficient of a resonant frequency are both decreased with increasing the degree of order of octahedral-site ions in Ba(Zn0.8Ni0.1Co0.1)1/3(Ta0.6Nb0.4)2/3O3 perovskite-type compound. The lattice parameter is also decreased with increasing the degree of order. The ordered structure is observed in the samples annealed at 1400°C, though it is not observed in the samples annealed at 1500°C. Besides, the ordered phase obtained at 1400°C is changed to a disordered phase by the annealing at 1500°C. These results indicate that the dielectric constant and the temperature coefficient of a resonant frequency of ordered perovskites can be controlled by controlling the degree of order.