Trichrome Synthesis of Rare Earth Doped Calcium Tungstate Fluorescent Powder

Fluorescent powder has important application value in many sectors of national economy. The most widely used fluorescent lamp, followed by LED display screen. In addition, fluorescent powder can also be used on oscilloscopes and radar fluorescent screens, as well as electronic-photon converters, nuclear radiation displays and X-ray sensitization screens. In short, the use of fluorescent powder is extensive, and its scope of use is expanding year by year.

A preparation method of rare earth doped calcium tungstate fluorescent powder synthesized by hydrothermal method has been proposed. Because the self-luminescence of calcium tungstate is blue, only red and green fluorescent powder need to be synthesized. The steps are as follows:

1. Red fluorescent powder:
(1) Rare earth lanthanum nitrate solution with molar concentration of 0.01 mol/L was prepared, and the quality ratio was 1:5-4:5. After peeling, the spongy cuttlefish bones and ammonium tungstate were added.

(2)The mixture was reacted for 24 hours at 120-180 ℃ and then cooled to room temperature naturally.

(3)The reaction products were washed with distilled water, dried and scorched for 2 hours at 200 1000 ℃. Rare earth doped calcium tungstate fluorescent powder with different luminescent properties was obtained.

The samples after calcination were tested by fluorescence. Fluorescence analysis showed that the product had a high luminescence intensity at 414 nm under 240 nm excitation when it was burned above 700 C. The lanthanum doped calcium tungstate fluorescent powder emitted red fluorescence under ultraviolet lamp.

2. Green Fluorescent Powder
(1) Rare Earth Terbium nitrate solution with molar concentration of 0.01 mol/L was prepared, and the spongy cuttlefish bones and ammonium tungstate were peeled with the mass ratio of 1:5 to 4:5.

(2)The mixture was reacted for 24 hours at 120-180 ℃ and then cooled to room temperature naturally.

(3)The reaction products were washed with distilled water, dried and scorched for 2 hours at 200 1000 ℃. Rare earth doped calcium tungstate fluorescent powder with different luminescent properties was obtained.

The samples after calcination were tested by fluorescence. Fluorescence analysis showed that the product had high luminescence intensity at 383, 417 and 438 nm under 240 nm light excitation when it was burned above 900 ℃. The terbium-doped calcium tungstate fluorescent powder emitted green fluorescence under ultraviolet lamp.

The hydrothermal reaction method has the advantages of simple process, high production efficiency, low equipment investment, no pollution in the whole production process, and easy to dope rare earth ions into fluorescent powder. After high temperature calcination, the organic impurities and other impurities in the product are removed, and the rare earth doped calcium tungstate fluorescent powder with good luminescent properties is obtained. Lamps, neon lights, X-ray fluorescent screens and other aspects can be more widely used.

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