Influence of the pH on Al2O3:CuO pigments prepared by a polymeric precursor method

copper (ii) aluminate, cual2o4, which is known to be an inverse spinel contains a d9 metal ion and possesses interesting electronic, magnetic and catalytic properties and is used in industry as ceramic pigments, coatings and catalysts. al2o3 with 10 mol% cu (alcu10) was synthesized by the polymeric precursor method varying the ph of the precursor solution with addition of ammonium hydroxide and ethylenediamine. it was shown that the pyrolysis of the polymeric chain occurs in higher temperatures for samples prepared in higher values of ph. the colorimetric coordinates exhibit dependence with ph and with the increase of annealing temperature. alcu10 samples prepared with higher values of ph present lower values of colorimetric coordinates, indicating alterations in its color. the luminosity parameters l* increase also as a function of ph.