The present invention provides a powder for forming a black light-shielding film having a specific surface area of 20 to 90 m.sup.2/g, which is measured by the BET method, comprising zirconium nitride as a main component, and containing magnesium and/or aluminum. If containing the magnesium, the content of the magnesium is 0.01 to 1.0% by mass relative to 100% by mass of the powder for forming a black light-shielding film, and if containing the aluminum, the content of the aluminum is 0.01 to 1.0% by mass relative to 100% by mass of the powder for forming the black light-shielding film.

The present invention provides a powder for forming a black light-shielding film having a specific surface area of 20 to 90 m.sup.2/g, which is measured by the BET method, comprising zirconium nitride as a main component, and containing magnesium and/or aluminum. If containing the magnesium, the content of the magnesium is 0.01 to 1.0% by mass relative to 100% by mass of the powder for forming a black light-shielding film, and if containing the aluminum, the content of the aluminum is 0.01 to 1.0% by mass relative to 100% by mass of the powder for forming the black light-shielding film.

A zirconium nitride powder which has a specific surface area of 20 to 90 m.sup.2/g as measured by a BET method, has a peak corresponding to zirconium nitride but does not have a peak corresponding to zirconium dioxide, a peak for lower zirconium oxide or a peak corresponding to lower zirconium oxynitride in an X-ray diffraction profile, and the light transmittance X at 370 nm is at least 18%, the light transmittance Y at 550 nm is 12% or less and the ratio (X/Y) of the light transmittance X at 370 nm to the light transmittance Y at 550 nm is 2.5 or more in the transmission spectra of a dispersion that contains the powder at a concentration of 50 ppm.

A zirconium nitride powder which has a specific surface area of 20 to 90 m.sup.2/g as measured by a BET method, has a peak corresponding to zirconium nitride but does not have a peak corresponding to zirconium dioxide, a peak for lower zirconium oxide or a peak corresponding to lower zirconium oxynitride in an X-ray diffraction profile, and the light transmittance X at 370 nm is at least 18%, the light transmittance Y at 550 nm is 12% or less and the ratio (X/Y) of the light transmittance X at 370 nm to the light transmittance Y at 550 nm is 2.5 or more in the transmission spectra of a dispersion that contains the powder at a concentration of 50 ppm.

The present invention provides a zirconium nitride powder comprising zirconium, nitrogen, and oxygen as main components, wherein the zirconium concentration is 73 to 82% by mass, the nitrogen concentration is 7 to 12% by mass, and the oxygen concentration is 15% by mass or less; in the transmission spectra of a dispersion having a powder concentration of 50 ppm, a light transmittance X at 370 nm is at least 12% and a light transmittance Y at 550 nm is 12% or less; and the ratio (X/Y) of the light transmittance X at 370 nm to the light transmittance Y at 550 nm is at least 1.4.

The present invention provides a zirconium nitride powder comprising zirconium, nitrogen, and oxygen as main components, wherein the zirconium concentration is 73 to 82% by mass, the nitrogen concentration is 7 to 12% by mass, and the oxygen concentration is 15% by mass or less; in the transmission spectra of a dispersion having a powder concentration of 50 ppm, a light transmittance X at 370 nm is at least 12% and a light transmittance Y at 550 nm is 12% or less; and the ratio (X/Y) of the light transmittance X at 370 nm to the light transmittance Y at 550 nm is at least 1.4.

A process for manufacturing a compound in powder form, wherein said compound is the reaction product of (i) at least one metal and/or metalloid, and (ii) at least one further element that is more electronegative than the metal and/or metalloid, which process includes steps of: mixing at least one oxide of said at least one metal and/or metalloid with a reducing agent including Ca or Mg granules or powder, and/or calcium hydride or magnesium hydride in granule or powder form, to form a mixture; exposing the mixture to a source of said at least one further element; maintaining said mixture under a H.sub.2 atmosphere at a temperature of from 950 C. to 1500 C. for 1-10 hours; and, recovering said compound in powder form; wherein said at least one further element is selected from carbon, nitrogen, boron, silicon and mixtures thereof. A compound in powder form obtainable by such a process.

A surface treatment layer for a titanium-containing substrate includes a disordered metal oxide lattice having metal nitride compounds doped in the disordered metal oxide lattice. A method of surface treating a metal substrate includes introducing oxygen to a titanium-containing substrate to thereby form an oxide layer within the titanium-containing substrate, and, after the step of introducing oxygen, introducing nitrogen to the titanium-containing substrate to thereby modify the oxide layer to form a surface treatment layer.

The present invention is directed to crystalline solids having an empirical formula of M.sub.2A.sub.2X, wherein M is at least one Group IIIB, IVB, VB, or VIB metal, preferably Cr, Hf, Sc, Ti, Mo, Nb, Ta, V, Zr, or a combination thereof; wherein A is Al, Ga, Ge, In, Pb, or Sn, or a combination thereof; and each X is C.sub.xN.sub.y, where x+y=1. In some particular embodiments, the crystalline composition has a unit cell stoichiometry of Mo.sub.2Ga.sub.2C.

The present invention is directed to crystalline solids having an empirical formula of M.sub.2A.sub.2X, wherein M is at least one Group IIIB, IVB, VB, or VIB metal, preferably Cr, Hf, Sc, Ti, Mo, Nb, Ta, V, Zr, or a combination thereof; wherein A is Al, Ga, Ge, In, Pb, or Sn, or a combination thereof; and each X is C.sub.xN.sub.y, where x+y=1. In some particular embodiments, the crystalline composition has a unit cell stoichiometry of Mo.sub.2Ga.sub.2C.