The activated Al-Sr alloy powder was put immediately into boiling pure water

with liquid-solid(ratio) of 4:1.The system was kept isothermal and stirred until white hydrolysates appears.The hydrolysates contain the mixture of Sr(OH)

2

·8H

2

O and Al(OH)

3

in main

included a little Al(OH)

3

AlOOH

SrCO

3

and 3SrO·Al

2

O

3

· 6H

2

O.After heat treatment at 700℃ for 1 h

the mixture of SrO and α-Al

2

O

3

γ-Al

2

O

3

were formed.As a precursor

the hydrolysates after heat treatment had been used to prepare long after phosphor Eu

Dy co-doped SrAl

2

O

4

at 1300℃ for 1 h.The crystal structure of hydrolysates and Eu

Dy co-doped SrAl

2

O

4

were analyzed by XRD.The luminescent properties of long afterglow material were studied.The(results) showed that the crystal structure of phosphor is β phase SrAl

2

O

4

the emission spectra of Eu and Dy co-doped SrAl

2

O

4

lied near 520 nm

resulted from the character transition of 4f5d-4f of Eu

2+

ion.The method can improve afterglow properties dramatically.The initial luminescent intensity of long afterglow material reached 18 cd/m

2

and the duration time lasted 46 h.The improved properties are related to precipitation mechanism of AlSr alloy hydrolysates.With this procedure

SrO and Al

2

O

3

will disperse evenly to effectively enlarge the contact area of the components

shorten the diffusive distance.As a result the sintering temperature could be decreased

while the reaction speed and the long afterglow fluorescent properties of the materials could be improved.