(Hf.sub.1-x Zr.sub.x).sub.3 P.sub.2 O.sub.11 luminescent material, method of preparation and X-ray intensifying screen containing same

A process for producing a luminescent material having the oxide composition of 3:1 molar proportions of (Hf.sub.1-x Zr.sub.x)O.sub.2 :

• P.sub.2 O.sub.5, and the empirical formula (Hf.sub.1-x Zr.sub.x).sub.3 P.sub.2 O.sub.11, where x is within the range of 0 to 0.5, said luminescent material exhibiting a characteristic peak emission at about 350 nanometers with a band width of about 70 nanometers when excited by x-rays, the process comprising:
• a. first forming a mixture of compounds selected from the group consisting of (Hf.sub.1-x Zr.sub.x)O.sub.2, P.sub.2 O.sub.5 and precursors thereof, which mixture upon an oxide basis corresponds to a molar ratio of (Hf.sub.1-x Zr.sub.x)O.sub.2 :P.sub.2 O.sub.5 within the range of about 2.85 to 3.15;
• and
• b. firing the mixture at a temperature within the range of about 1400.degree. to 2,200.degree. C, for a time sufficient to result in a luminescent material having said characteristic peak.

An x-ray intensifying screen for use with conventional silver halide emulsion x-ray film to intensify an exposed image on the film, the screen comprising:

• a. a base layer of a material substantially transparent to x-rays, but substantially opaque to visible and ultraviolet radiation;
• and
• b. a layer of an x-ray excitable luminescent material secured to base layer,
• characterized in that the luminescent material consists essentially of particles having the oxide composition of 3:1 molar proportions of (Hf.sub.1-x Zr.sub.x)O.sub.2 :P.sub.2 O.sub.5 , and the empirical formula (Hf.sub.1-x Zr.sub.x).sub.3 P.sub.2 O.sub.11 where x is within the range of 0 to 0.5, said luminescent material exhibiting a peak emission at about 350 nanometers with a band width of about 70 nanometers when excited by x-rays, whereby good resolution of the image is obtained without substantial crossover.

A process for producing a luminescent material having an oxide composition of 3:1 molar proportions of (Hf.sub.1-x Zr.sub.x)O.sub.2 :P.sub.2 O.sub.5, and the empirical formula (Hf.sub.1-x Zr.sub.x).sub.3 P.sub.2 O.sub.11, where x is within the range of 0 to 0.5, said luminescent material exhibiting a characteristic peak at about 350 nanometers with a band width of about 70 nanometers when excited by x-rays, and the material consisting essentially of large single-crystalline particles, the process comprising:

• a. first forming a mixture of compounds selected from the group consisting of (Hf.sub.1-x Zr.sub.x)O.sub.2, P.sub.2 O.sub.5 and precursors thereof, which mixture upon an oxide basis corresponds to a molar ratio of (Hf.sub.1-x Zr.sub.x)O.sub.2 :P.sub.2 O.sub.5 within the range of about 2.85 to 3.15;
• b. adding from about 10 to 100 mole percent of magnesium fluoride to the mixture;
• and
• c. firing the mixture at a temperature within the range of about 1200.degree. to 1600.degree. C for a time sufficient to result in a luminescent material having said characteristic peak.