Societe Europeenne Des Produits Refractaires

Alain Paul Bernard Zanoli

Michel Marc Gaubil

Emmanuel Jean-Marie Sertain

Bruno Pascal Albert Aleonard

Yves Marcel L&eacute;on Boussant-Roux

A process for producing fused alumina-zirconia grits includes mixing raw materials suitable to produce grits with the following chemical composition, in % by weight: ZrO+HfO: 10&#x2013;60%, AlO: 38&#x2013;90%, SiO: &#x3c;0.8%, and Impurities: &#x3c;1.2%. The process also includes adding carbon and aluminum metal to the mixture of raw materials to obtain a charged batch containing, in % by weight,: Carbon: 0.4&#x2013;1% Aluminum metal: 0.5&#x2013;2.5%. The process further includes melting the charged batch in an electric arc furnace with a voltage of 175&#x2013;205 V and a delivered specific electrical energy of 2.5 to 4 kWh per kg of charge.

Melted alumina-zirconia ceramic grains, abrasive tools and refractory parts produced from said grains

Oxidized alumina-zirconia-silica (AZS) refractories containing 40 wt % to 55 wt % Al O , 32 wt % to 45 wt % ZrO , 10 wt % to less than 16 wt % SiO and 1 wt % to 3 wt % of an alkali metal oxide selected from Na O, K O and mixtures thereof have a microstructure essentially comprising alpha-alumina crystals, free zirconia crystals, eutectic crystals and an intercrystalline vitreous phase. At least in an active area, more than 20% by number of the free zirconia crystals have a dendritic shape and are interleaved with each other and with eutectic crystals and at least 40% by number of the dendritic free zirconia crystals have a dimension greater than 300 &mgr;m.

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Avignon, France

Alain Paul Bernard Zanoli