MICROWAVE-ASSISTED SYNTHESIS OF Pr-ZrSiO4, AND Cr-Y AlO3 CERAMIC PIGMENTS

• Published in: Journal of the European Ceramic Society 2009-11, Vol.29 (14), p.2951-2957
• Main Authors: Blosi, M, Dondi, M, Albonetti, S, Baldi, G, Barzanti, A, Zanelli, C
• Format: Article
• Language: English
• ISSN: 0955-2219

A two-step route was used for the synthes is of Pr-ZrSiO4, V-ZrSiO4 and Cr-YAlO3 pigments. The total synthesis time was reduced many hours down to a few minutes. Industrial were pelletised and underwen t a short in a conventional electric furnace pri or to heating in microwave oven (2.45 GHz, 800 W or paused). Pre-heating was necessary to reach a level at which pigment precursors were activated er microwave irradiation. Activation kinetics was b y measuring the external temperature of the during MW irradiation and the internal at the end of th e heating process. Pigments were by colorimetr y and XRPD with Rietveld The V-ZrSiO4 system was easily activated, at temperature of 300 C, with good reaction yield colour performance but it was diffi cult to keep control, as temperatures exceeded 1200 C. The system was activated after pre-heating at ove r C and it exhibited slow kinetics, resulting in a r eaction yield and unsatisfactory colour. The pigmen t was formed with colour and reaction close to those o f the corresponding industrial even when it was pre -heated at 800 C or more. behaviour of silica phases was observed in zircon particularly after lower pre-he ating This consisted of an early transformatio n of (present as precursor) into cristobalite and abu amorphous phase, before the SiO2 + ZrO2 to ZrSiO4 sformation occurred.