| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a transparent, polycrystalline ceramic which is a material having a high refractive index, a high Abbe number and/or an excellent specific relative partial dispersion as well as low stress-induced birefringence, where these parameters cannot be achieved using conventional glass, single-crystalline materials and crystalline ceramics or materials. <P>SOLUTION: The ceramic comprises crystallites of the formula A<SB>x</SB>C<SB>u</SB>B<SB>y</SB>D<SB>v</SB>E<SB>z</SB>F<SB>w</SB>, wherein A and C are selected from the group consisting of Li<SP>+</SP>, Na<SP>+</SP>, Be<SP>2+</SP>, Mg<SP>2+</SP>, Ca<SP>2+</SP>, Sr<SP>2+</SP>, Ba<SP>2+</SP>, Al<SP>3+</SP>, Ga<SP>3+</SP>, In<SP>3+</SP>, C<SP>4+</SP>, Si<SP>4+</SP>, Ge<SP>4+</SP>, Sn<SP>2+/4+</SP>, Sc<SP>3+</SP>, Ti<SP>4+</SP>, Zn<SP>2+</SP>, Zr<SP>4+</SP>, Mo<SP>6+</SP>, Ru<SP>4+</SP>, Pd<SP>2+</SP>, Ag<SP>2+</SP>, Cd<SP>2+</SP>, Hf<SP>4+</SP>, W<SP>4+/6+</SP>, Re<SP>4+</SP>, Os<SP>4+</SP>, Ir<SP>4+</SP>, Pt<SP>2+/4+</SP>, Hg<SP>2+</SP>and mixtures thereof; B and D are selected from the group consisting of Li<SP>+</SP>, Na<SP>+</SP>, K<SP>+</SP>, Mg<SP>2+</SP>, Al<SP>3+</SP>, Ga<SP>3+</SP>, In<SP>3+</SP>, Si<SP>4+</SP>, Ge<SP>4+</SP>, Sn<SP>4+</SP>, Sc<SP>3+</SP>, Ti<SP>4+</SP>, Zn<SP>2+</SP>, Y<SP>3+</SP>, Zr<SP>4+</SP>, Nb<SP>3+</SP>, Ru<SP>3+</SP>, Rh<SP>3+</SP>, La<SP>3+</SP>, Lu<SP>3+</SP>, Gd<SP>3+</SP>and mixtures thereof; E and F are selected from the group consisting of the divalent anions of S, Se and O and mixtures thereof; x, u, y, v, z and w satisfy the formulae 0.125<(x+u)/(y+v)≤0.55 and z+w=4, with the proviso that when A=C=Mg<SP>2+</SP>and B=D=Al<SP>3+</SP>, E and F cannot both be O (oxygen). <P>COPYRIGHT: (C)2011,JPO&INPIT |
