A process of making a dense, cohesive and uniform aluminum oxide coating on a metallic substrate includes electrodepositing polynuclear aluminum oxide hydroxide clusters from a polynuclear aluminum oxide hydroxide cluster solution on a metallic substrate to form a precursor coating, and post-treating the precursor coating to form a final aluminum oxide coating on the metallic substrate.

A process of making a dense, cohesive and uniform aluminum oxide coating on a metallic substrate includes electrodepositing polynuclear aluminum oxide hydroxide clusters from a polynuclear aluminum oxide hydroxide cluster solution on a metallic substrate to form a precursor coating, and post-treating the precursor coating to form a final aluminum oxide coating on the metallic substrate.

The present invention provides a layered double hydroxide with improved conductivity, a layered double hydroxide and a composite material containing the layered double hydroxide. The layered double hydroxide is represented by the general formula: [Mg.sup.2+.sub.(1-y)M1.sup.+.sub.y].sub.1-x[Al.sup.3+.sub.(1-z)M2.sup.+.sub.z].sub.x(OH).sub.2A.sup.n.sub.x/n.mH.sub.2O, wherein 0.1x0.4, 0y0.95, and 0z0.95, provided that both y and z are not 0 at the same time; =1 or 2; =2 or 3; A.sup.n is an n-valent anion, provided that n is an integer of 1 or greater; m0; M1.sup.+ is a cation of at least one substituent element selected from monovalent elements, transition metal elements, and other elements with an ionic radius greater than that of Mg.sup.2+; and M2.sup.+ is a cation of at least one element selected from divalent elements, transition metals, and other elements with an ionic radius greater than that of Al.sup.3+.

The present invention provides a layered double hydroxide with improved conductivity, a layered double hydroxide and a composite material containing the layered double hydroxide. The layered double hydroxide is represented by the general formula: [Mg.sup.2+.sub.(1-y)M1.sup.+.sub.y].sub.1-x[Al.sup.3+.sub.(1-z)M2.sup.+.sub.z].sub.x(OH).sub.2A.sup.n.sub.x/n.mH.sub.2O, wherein 0.1x0.4, 0y0.95, and 0z0.95, provided that both y and z are not 0 at the same time; =1 or 2; =2 or 3; A.sup.n is an n-valent anion, provided that n is an integer of 1 or greater; m0; M1.sup.+ is a cation of at least one substituent element selected from monovalent elements, transition metal elements, and other elements with an ionic radius greater than that of Mg.sup.2+; and M2.sup.+ is a cation of at least one element selected from divalent elements, transition metals, and other elements with an ionic radius greater than that of Al.sup.3+.

An alumina sintered body of the present invention has a degree of c-plane orientation of 5% or more, which is determined by a Lotgering method using an X-ray diffraction profile in a range of 2=20 to 70 obtained under X-ray irradiation, and an XRC half width of 15.0 or less in rocking curve measurement, an F content of less than 0.99 mass ppm when measured by D-SIMS, a crystal grain diameter of 15 to 200 m, and 25 or less pores having a diameter of 0.2 m to 1.0 m when a photograph of a viewing area 370.0 m in a vertical direction and 372.0 m in a horizontal direction taken at a magnification factor of 1000 is visually observed.

Provided is a porous lithium composite phosphate-based compound containing lithium and having open pores formed in primary particles. As the open pores are formed in the primary particles themselves, a contact area between an electrolyte and the lithium composite phosphate-based compound is maximized, and low conductivity is compensated for, such that a diffusion rate of lithium ions is remarkably increased, and when the lithium composite phosphate-based compound is used as an active material of a secondary battery, the secondary battery may be charged and discharged at a high speed. Additionally, there are advantages in that an electrode density may be significantly increased in addition to the increase in the diffusion rate of the lithium ions, and charge and discharge cycle characteristics may be significantly stable.

The invention relates to mixed alkali-aluminum phosphites of the formula (I)
Al.sub.2.00M.sub.z(HPO.sub.3).sub.y(OH).sub.vx(H.sub.2O).sub.w(I)
in which
M represents alkali metal ions,
z is 0.01 to 1.5,
y is 2.63 to 3.5,
v is 0 to 2,
w is 0 to 4;
to a process for preparation thereof and to the use thereof.

The invention relates to mixed alkali-aluminum phosphites of the formula (I)
Al.sub.2.00M.sub.z(HPO.sub.3).sub.y(OH).sub.vx(H.sub.2O).sub.w(I)
in which
M represents alkali metal ions,
z is 0.01 to 1.5,
y is 2.63 to 3.5,
v is 0 to 2,
w is 0 to 4;
to a process for preparation thereof and to the use thereof.

The present invention aims to provide techniques for preparing complexes of a hydrotalcite and a fiber. The complexes of a hydrotalcite and a fiber can be synthesized efficiently by synthesizing the hydrotalcite in an aqueous system in the presence of the fiber.

The present invention aims to provide techniques for preparing complexes of a hydrotalcite and a fiber. The complexes of a hydrotalcite and a fiber can be synthesized efficiently by synthesizing the hydrotalcite in an aqueous system in the presence of the fiber.