Ce-Mn activated calcium fluorophosphate(FAP:Ce

Mn)

as a new kind of yellow phosphor with high efficiency

which is promising in two-component blend lamp

has been prepared resently.Ce

3+

was compensated in charge by additional Na

+

in this material

lead to a high lumen decay on lamps.In this paper

a sort of high efficient FAP:Ce

Mn phosphor without Na

+

(Ce

3+

is compensated by excessive F

-

)is reported.The synthesis condition of this material is described

and the formation mechanism of this material is analysed.The firing temperature dependence of lumen efficiency of this phosphor in three types of different atmosphere is shown in Fig.1.It can be seen that the reducing atmosphere is favourable for the formation of high efficient phosphor and that the optimum firing temperature is 900℃.The effect of initial component on the lumen efficiency and lumen maintenance is studied and shown in Fig.2-7.The following results are obtained from these experiments.(1)The effect of the ratio of

M

M

/

M

P

in initial component on lumen efficiency of FAP:Ce

Mn is not obvious

but that on lumen maintanence is striking.The phosphor with the best lumen maintenance can be prepared while the ratio of

M

M

/

M

P

is about 1.64.(2)The emission peaks of both Ce

3+

amd Mn

2+

shift to short wavelength if the amount of fluorine in initial component incresses.The most efficient phosphor can be prepared only one excessive fluorine

exists and the optimum ratio of

M

M

/

M

P

is 2:3(in excess of 100% in stoichiom-etric composition).(3)The phosphor of FAP:Ce

Mn with Na

+

as compensator can give slightly higher initial lumen efficiency

but its lumen decay is more rapid than that without Na

+

.Considering the requirement in the application of lamp

the phosphor without Na

+

is more advantageous.