The characteristics of ZnS:Mn powder phosphors fired in HC1 atmosphere are systematically described.This technology is with lower sintering temperature and shorter firing period because of the strong mineralization of HC1 gas. Thus

the phosphors obtained not only crystallize well

but also have smaller particle size. The brightness of the phosphors under UV and DC excitation is higher than that of phosphors produced in conventional way.In HC1 atmosphere

the recrystallization of the material is very rapid. The process can be finished in 10 min. The content ratio of hexagonal to cubic phase formed in sintering temperature is hardly shifted by slow cooling or annealing. This may be the effect of C1 induced by HC1 atmosphere. The experiment also suggests that ZnS raw material play an important role in forming crystalphase.In order to know the effect of different content ratio of crystalphase on DCEL

some ZnS:Mn samples with variable hexagonal phase composition were coated with copper and then aged under electric field. It is observed that the samples containing less hexagonal phase are better in maintenance. Thus

it may be concluded that the DCEL lifetime can be improved by appropriately reducing hexagonal phase content.In view of the symmetry of crystal field

hexagonal or cubic phase may affect the splitting of the activator’s energy level. Therefore

the brightness and the location of spectrum peak

but in spite of maintenance

can be influenced. So

the distinction of the lifetime should not be caused by different crystalphase. According to the model of Cu

+

migration

it is considered that the problem of maintenance is associated with the property of Cu

x

S phase. Hexagonal and cubic phase posses different crystal lattice

and their ratio determines the structure of Cu

x

S which grows on those lattice. This has been identified from experimental data. The copper-coated ZnS raw material with cubic lattice shows high resistivity. And ZnS: Mn fired in lower temperature also has low conductivity because it contains more cubic phase composition on that preparing condition. However

the resistivity is usually lower for the material containing more hexagonal phase content. Generally

the maintenance characteristic is better for the sample with higher resistivity and is worse for that with lower one. So

the stability of Cu

x

S phase is affected by the hexagonal phase content and that leads to different DCEL lifetime.This experiment suggests that the DCEL phosphors with higher brightness and longer lifetime are possible to be prepared by the sintering technology using HC1 atmosphere.