The afterglow phosphor CaAl

2

O

4

:Eu

2+

Nd

3+

is prepared utilizing the redox reaction of respective metal nitrates and urea by combustion synthesis with ignition temperatures of 600℃.The X-ray diffraction(analysis) showed that it is coincident with the JCPDS Card(No.23-1036) and its crystal structure is CaAl

2

O

4

which belongs to monoclinic phase and the crystal lattice constant is as follows:

a

=0.8698 nm

b

=0.8092 nm

c

=1.5208 nm.With the invariable concentration of metallic ions nitrate

a series of phosphor samples were synthesized by altering the ratio of urea and nitrate.The emission spectra and excitation spectra of the phosphor were investigated.The excitation spectra of CaAl

2

O

4

:Eu

2+

Nd

3+

showed a double peak broadband structure.The main peak located at 352 nm and a shoulder peak at 266 nm.The quantity of urea has obvious influence on the emission spectrum of CaAl

2

O

4

:Eu

2+

Nd

3+

.When the quantity of urea exceed double of theoretic quantity

adequate reducing gas produced in the process of combustion reaction benefit to the form of Eu

2+

luminescent center

so emission spectra of CaAl

2

O

4

:Eu

2+

Nd

3+

consist of characteristic broad band emission of Eu

2+

.Contrast this

inadequate reducing gas benefit to form of Eu

3+

luminescent center

so when the quantity of urea less than double of theoretic quantity

the emission spectra exhibit characteristic narrowband emission of Eu

3+

.The samples are fired at 1000℃ for 2h in an active carbon atmosphere in order to deoxidize residual Eu

3+

to Eu

2+

and eliminate impurity brought by combustion synthesis.This is beneficial to promote the performance of luminescence.The decay curves of phosphor with different quantity of urea were measured.The change of ureas quantity affected on the afterglow character of CaAl

2

O

4

:Eu

2+

Nd

3+

distinctly and the optimal quantity of urea is 5 times of theoretic quantity.When more urea was used in the experiment

the luminescent intensity will decrease and the lasting time will be shorten.