A lead-free piezoelectric ceramic material has the general chemical formula xBiCoO3-y(Bi0.5Na0.5)TiO3-z(Bi0.5K0.5)TiO3, xBiCoO3-y(Bi0.5Na0.5)TiO3-zNaN-bO3, xBiCoO3-y(Bi0.5Na0.5)TiO3-zKNbO3, xBiCoO3-yBi(Mg0.5Ti0.5)O3-z(Bi0.5Na0.5)TiO3, xBiCoO3-yBa-TiO3-z(Bi0.5Na0.5)TiO3, or xBiCoO3-yNaNbO3-zKNbO3; wherein x+y+z=1, and x, y, z≠0.

A lead-free piezoelectric ceramic material has the general chemical formula xBiCoO3-y(Bi0.5Na0.5)TiO3-z(Bi0.5K0.5)TiO3, xBiCoO3-y(Bi0.5Na0.5)TiO3-zNaN-bO3, xBiCoO3-y(Bi0.5Na0.5)TiO3-zKNbO3, xBiCoO3-yBi(Mg0.5Ti0.5)O3-z(Bi0.5Na0.5)TiO3, xBiCoO3-yBa-TiO3-z(Bi0.5Na0.5)TiO3, or xBiCoO3-yNaNbO3-zKNbO3; wherein x+y+z=1, and x, y, z≠0.

A method of forming a thermal barrier coating is disclosed. The method may include providing a solution containing strontium and niobium and applying the solution to a substrate via a chemical solution deposition process to form a first film layer on the substrate. The method may further include pyrolyzing the first film layer and annealing the first film in an air atmosphere to form a strontium niobate coating.

A ceramic substrate is formed of a polycrystalline ceramic and has a supporting main surface. The supporting main surface has a roughness of 0.01 nm or more and 3.0 nm or less in terms of Sa. The number of projections and depressions with a height of 1 nm or more in a square region with 50 μm sides on the supporting main surface is less than 5 on average, and the number of projections and depressions with a height of 2 nm or more in the square region is less than 1 on average.

Both single phase lead-free cubic pyrochlore bismuth zinc niobate (BZN)-based dielectric materials with a chemical composition of Bi.sub.1.5Zn.sub.(0.5+y)Nb.sub.(1.5−x)Ta.sub.(x)O.sub.(6.5+y), with 0≦x<0.23 and 0≦y<0.9 and films with these average compositions with Bi.sub.2O.sub.3 particles in an amorphous matrix and a process of manufacture thereof. The crystalline BZNT-based dielectric material has a relative permittivity of at least 120, a maximum applied electric field of at least 4.0 MV/cm at 10 kHz, a maximum energy storage at 25° C. and 10 kHz of at least 50 J/cm.sup.3 and a maximum energy storage at 200° C. and 10 kHz of at least 22 J/cm.sup.3. The process is a wet chemical process that produces thin films of Bi.sub.1.5Zn.sub.(0.5+y)Nb.sub.(1.5−x)Ta.sub.(x)O.sub.(6.5+y) without the use of 2-methoxyethanol and pyridine.

Both single phase lead-free cubic pyrochlore bismuth zinc niobate (BZN)-based dielectric materials with a chemical composition of Bi.sub.1.5Zn.sub.(0.5+y)Nb.sub.(1.5−x)Ta.sub.(x)O.sub.(6.5+y), with 0≦x<0.23 and 0≦y<0.9 and films with these average compositions with Bi.sub.2O.sub.3 particles in an amorphous matrix and a process of manufacture thereof. The crystalline BZNT-based dielectric material has a relative permittivity of at least 120, a maximum applied electric field of at least 4.0 MV/cm at 10 kHz, a maximum energy storage at 25° C. and 10 kHz of at least 50 J/cm.sup.3 and a maximum energy storage at 200° C. and 10 kHz of at least 22 J/cm.sup.3. The process is a wet chemical process that produces thin films of Bi.sub.1.5Zn.sub.(0.5+y)Nb.sub.(1.5−x)Ta.sub.(x)O.sub.(6.5+y) without the use of 2-methoxyethanol and pyridine.

A dielectric composition containing a complex oxide represented by the formula of xAO-yBO-zC.sub.2O.sub.5 as the main component, wherein A represents at least one element selected from the group including Ba, Ca and Sr, B represents Mg, and C represents at least one element selected from the group including Nb and Ta, and x, y and z meet the following conditions, x+y+z=1.000, 0.198≦x≦0.375, 0.389≦y≦0.625, and x/3≦z≦x/3+1/9.

A dielectric composition containing a complex oxide represented by the formula of xAO-yBO-zC.sub.2O.sub.5 as the main component, wherein A represents at least one element selected from the group including Ba, Ca and Sr, B represents Mg, and C represents at least one element selected from the group including Nb and Ta, and x, y and z meet the following conditions, x+y+z=1.000, 0.198≦x≦0.375, 0.389≦y≦0.625, and x/3≦z≦x/3+1/9.

A dielectric composition containing a complex oxide represented by the formula of xAO-yBO-zC.sub.2O.sub.5 as the main component, wherein A represents at least one element selected from the group including Ba, Ca and Sr, B represents Mg, and C represents at least one element selected from the group including Nb and Ta, and x, y and z meet the following conditions, x+y+z=1.000, 0.000<x≦0.281, 0.625≦y<1.000, and 0.000<z≦0.375.

A dielectric composition containing a complex oxide represented by the formula of xAO-yBO-zC.sub.2O.sub.5 as the main component, wherein A represents at least one element selected from the group including Ba, Ca and Sr, B represents Mg, and C represents at least one element selected from the group including Nb and Ta, and x, y and z meet the following conditions, x+y+z=1.000, 0.000<x≦0.281, 0.625≦y<1.000, and 0.000<z≦0.375.