The phosphor of BaSi

2

O

5

:Pb

2+

has been widely used for manufacturing of black light lamps and treating many types of skin disease such as psoriasis

vitiligo

atopic dermatitis and so on.However

the detailed informations about the mechanism of flux BaF

2

used for preparing BaSi

2

O

5

:Pb

2+

phosphor can not be found in literature.The aim of this research is to work out the mechanism of flux BaF

2

in the process of preparing BaSi

2

O

5

:Pb

2+

.BaSi

2

O

5

:Pb

2+

sample was prepared by solid state reaction method at high temperature.Mixing compounds of barium and silicon which upon heating will react to form barium disilicate with a activating proportion Pb (NO

3

)

2

.The firing temperature is approximately 1100℃.Crystal structure of BaSi

2

O

5

:Pb

2+

phosphor is β-BaSi

2

O

5

.Ba

2+

was substituted by Pb

2+

partly in BaSi

2

O

5

lattice so the XRDpattern of BaSi

2

O

5

:Pb

2+

phosphor is identical with BaSi

2

O

5

crystal.Effect of BaF

2

concentration on ultraviolet intensity was studied.Mechanism that the addition of flux BaF

2

promotes the solid reaction and enhances BaSi

2

O

5

:Pb

2+

ultraviolet emission intensity was investigated by X-ray diffraction

heat-flux differential scanning calorimetry

and photoluminescence.Results indicate that BaSi

2

O

5

:Pb

2+

phosphor forms at 800℃ by adding BaF

2

.High temperature firing with a small amount of BaF

2

results in a phosphor with high emission intensity

BaSi

2

O

5

:Pb

2+

emission intensity reach its maximum when the amounts of flux BaF

2

is 8%.BaF

2

and SiO

2

combine to form SiF

4

and BaSi

2

O

5

then the formed SiF

4

will react with BaCO

3

to form BaSi

2

O

5

again.The addition of flux BaF

2

promote the solid state reaction

the temperature forming BaSi

2

O

5

:Pb

2+

phosphor was reduced to 800℃ and it is consistent with thermodynamics theory.