A piezoelectric composition including manganese and a complex oxide having a perovskite structure represented by a general formula ABO.sub.3, wherein an A site element in the ABO.sub.3 is potassium or potassium and sodium, a B site element in the ABO.sub.3 is niobium, a concentration distribution of the manganese has a variation, and the variation shows a CV value of 35% or more and 440% or less.

A method for manufacturing a dense layer that includes: supplying a substrate and a suspension of non-agglomerated nanoparticles of a material P; depositing a layer on the substrate using the suspension; drying the layer thus obtained; and densifying the dried layer by mechanical compression and/or heat treatment. The method is characterised in that the suspension of non-agglomerated nanoparticles of material P includes nanoparticles of material P having a size distribution having a value of D50. The distribution includes nanoparticles of material P of a first size D1 between 20 nm and 50 nm, and nanoparticles of material P of a second size D2 characterised by the value D50 being at least five times less than that of D1, or the distribution has a mean size of nanoparticles of material P less than 50 nm, and a standard deviation to mean size ratio greater than 0.6.

The invention belongs to the field of electronic ceramics and its manufacturing, in particular to the modified NiO-Ta.sub.2O.sub.5-based microwave dielectric ceramic material sintered at low temperature and its preparation method. It is guided by ion doping modification, not only considering the substitution of ions with similar radius, such as Zn.sup.2+ replacing Ni.sup.2+ ions, V.sup.5+ replacing Ta.sup.5+ ions; Meanwhile, the selected doped oxide still has the property of low melting point. Therefore, the microwave dielectric properties of NiO-Ta.sub.2O.sub.5-based ceramic material can be improved and the appropriate sintering temperature can be reduced. In the invention, by adjusting the molar content of each raw material, the NiO-Ta.sub.2O.sub.5-based ceramic material with low-temperature sintering, stable temperature and excellent microwave dielectric property is directly synthesized at one time, which can be widely applied to the technical field of LTCC.

The invention belongs to the field of electronic ceramics and its manufacturing, in particular to the modified NiO-Ta.sub.2O.sub.5-based microwave dielectric ceramic material sintered at low temperature and its preparation method. It is guided by ion doping modification, not only considering the substitution of ions with similar radius, such as Zn.sup.2+ replacing Ni.sup.2+ ions, V.sup.5+ replacing Ta.sup.5+ ions; Meanwhile, the selected doped oxide still has the property of low melting point. Therefore, the microwave dielectric properties of NiO-Ta.sub.2O.sub.5-based ceramic material can be improved and the appropriate sintering temperature can be reduced. In the invention, by adjusting the molar content of each raw material, the NiO-Ta.sub.2O.sub.5-based ceramic material with low-temperature sintering, stable temperature and excellent microwave dielectric property is directly synthesized at one time, which can be widely applied to the technical field of LTCC.

Provided is a piezoelectric ceramics including crystal grains each including: a first region that is formed of a perovskite-type metal oxide having a crystal structure in which a central element of a unit cell is located at an asymmetrical position; and a second region that is formed of a perovskite-type metal oxide having a crystal structure in which a central element of a unit cell is located at a symmetrical position, and that is present inside the first region, wherein a ratio of a cross-sectional area of the second region to a cross-sectional area of the piezoelectric ceramics is 0.1% or less.

A Li ion conductor having a composition different from a conventional composition is provided. The Li ion conductor contains at least one selected from a group Q consisting of Ga, V, and Al, Li, La and O. A part of an Li site is optionally substituted with a metal element D, a part of an La site is optionally substituted with a metal element E, and parts of Ga, V and Al sites are optionally substituted with a metal element J. A mole ratio of an amount of Li to a total amount of La, the element E, Ga, V, Al, and the element J is not lower than 8.1/5 and not higher than 9.5/5. A mole ratio of a total amount of Ga, V, and Al to a total amount of La and the element E is not lower than 1.1/3 and not higher than 2/3.

A dielectric ceramic composition comprising a main component comprising an oxide represented by:
U.sub.aX.sub.bY.sub.cZ.sub.d((Ca.sub.1-x-ySr.sub.xM.sub.y).sub.m(Zr.sub.1-u-vTi.sub.uHf.sub.v)O.sub.3).sub.1-a-b-c-d
wherein the elements defined by U, X, Y, Z and M and subscripts a, b, c, d, x, y, m, u and v are defined.

A dielectric ceramic composition comprising a main component comprising an oxide represented by:
U.sub.aX.sub.bY.sub.cZ.sub.d((Ca.sub.1-x-ySr.sub.xM.sub.y).sub.m(Zr.sub.1-u-vTi.sub.uHf.sub.v)O.sub.3).sub.1-a-b-c-d
wherein the elements defined by U, X, Y, Z and M and subscripts a, b, c, d, x, y, m, u and v are defined.

A temperature-stable modified NiO—Ta.sub.2O.sub.5-based microwave dielectric ceramic material and a preparation method thereof are provided. Using ion doping modification to form solid solution structure is an important measure to adjust microwave dielectric properties, especially the temperature stability. Based on formation rules of the solid solution, ion replacement methods are designed including Ni.sup.2+ ions are replaced by Cu.sup.2+ ions, and (Ni.sub.1/3Ta.sub.2/3).sup.4+ composite ions are replaced by [(Al.sub.1/2Nb.sub.1/2).sub.ySn.sub.1-y].sup.4+ composite ions, which considers that cations with similar ionic radii to Ni.sup.2+ and Ta.sup.5+ ions can be introduced into the NiTa.sub.2O.sub.6 ceramic for doping under the same coordination environment (coordination number=6), and therefore a ceramic material with the NiTa.sub.2O.sub.6 solid solution structure can be obtained. The microwave dielectric ceramic material with excellent temperature stability and low loss is finally prepared by adjusting molar contents of each of doped ions, and its microwave dielectric properties are excellent.

A temperature-stable modified NiO—Ta.sub.2O.sub.5-based microwave dielectric ceramic material and a preparation method thereof are provided. Using ion doping modification to form solid solution structure is an important measure to adjust microwave dielectric properties, especially the temperature stability. Based on formation rules of the solid solution, ion replacement methods are designed including Ni.sup.2+ ions are replaced by Cu.sup.2+ ions, and (Ni.sub.1/3Ta.sub.2/3).sup.4+ composite ions are replaced by [(Al.sub.1/2Nb.sub.1/2).sub.ySn.sub.1-y].sup.4+ composite ions, which considers that cations with similar ionic radii to Ni.sup.2+ and Ta.sup.5+ ions can be introduced into the NiTa.sub.2O.sub.6 ceramic for doping under the same coordination environment (coordination number=6), and therefore a ceramic material with the NiTa.sub.2O.sub.6 solid solution structure can be obtained. The microwave dielectric ceramic material with excellent temperature stability and low loss is finally prepared by adjusting molar contents of each of doped ions, and its microwave dielectric properties are excellent.