New doped mixed valency iron phosphate complex cpds. - useful as pigment in corrosion inhibiting paint or lacquer, and are prepd. by hydrothermal reaction

摘要

New Fe phosphate complexes (I) of mixed valency, contg. foreign metal ions, are of formulae (Fe(III)2Fe(II)l-x(M(II)x)(PO4)2 (OH)2 (IA) and (Fe(III)M(II)3-xFe(IIx)(PO4)3.2H2O (IB); M = Zn and/or Ni in (IA) and M = Zn, Ni and/or Mn in (IB); x = between 0 and 1. (I) with M = Zn, Ni and/or Mn are prepd. (claimed) by hydrothermal reaction of mixts. of Fe oxides and/or phosphates with M salts, phosphophyllite and/or phosphation slurry with acid contg. P in a sealed reactor, then cooling to room temp., releasing the pressure, sepg. the (I) ppte. from the soln. contg. unreacted metal and phosphate ions and drying (I), opt. by heating. Operations before hydrothermal reaction are carried out at 5-100, pref. 15-30 deg C and an O2 pressure of 1-30, pref. 3-10 bar. USE/ADVANTAGE - (I) are claimed for use as corrosion inhibiting pigments in paints and lacquers. The corrosion inhibition is better than that of Zn phosphate and about the same as that of Zn chromate, whilst the toxicity problems associated with pigments contg. Pb or chromate are avoided. Phosphation slurry, accumulating in large amts. in the phosphation of car bodies, can be used as starting material. (6pp Dwg.No.0/0)