Patent ID: 9534169
Date: 2017-01-03
CPC Classifications: C04B,C09K,H01L

Claim:
1. A process for producing a pulverulent precursor material of the general composition I or II or III or IV: I: (Ca II: (Ca III: Z IV: (Z wherein X1 and X2 and X3 and X4 are each one activator or a combination of two or more activators; wherein the activator is selected from the group consisting of lanthanoids, Mn wherein Z is selected from the group consisting of Ca, Sr, Mg, and combinations thereof; wherein: 0≦y≦1 and 0≦a<1 and 0≦b<1 and 0<c≦1 and |δ|≦0.5 and 0≦x<1 and 0≦d<1; the process comprising: producing a pulverulent mixture of reactants, wherein the reactants comprise ions of the compositions I and/or II and/or III and/or IV, wherein a silicon nitride having a specific surface area of greater or equal than 5 m calcining the mixture under a protective gas atmosphere and at a temperature less than or equal to 1550° C.; and grinding the calcined mixture, wherein the pulverulent precursor material of the general composition I or II or III or IV is produced, wherein the pulverulent precursor material has a first grain size value d