Pflanz, K.K.PflanzChmiel, H.H.ChmielRiedel, R.R.Riedel2022-03-082022-03-081998https://publica.fraunhofer.de/handle/publica/304065The invention relates to a process for the production of coatings made of spinel (MgO*Al<-2 O<-3, MgAl<-2 O<-4 ), and carriers provided with a spinel coating, and in particular a process for the production of porous filtration membranes having a selective coating made of spinel. A mixed magnesium-aluminium-alkoxide (magnesium-aluminium double alkoxide) of the formula (I) or (II), MgAl<-2 (OR)<-8 or Mg<<Al(OR)<-4 >><-2 is hydrolyzed, whereby the residue R represents branched or linear alkyl groups having 1 to 10 C atoms, the resultant magnesium-aluminium hydroxide suspension is peptized with an acid, the peptized magnesium-aluminium hydroxide suspension is allowed to age until a colloid magnesium-aluminium hydroxide solution results, a carrier is coated with the colloid magnesium-aluminium hydroxide solution and the coated substrate is dried and calcined.de608610620660patent1991-4130969