Saint-Gobain Centre De Recherches Et D'etudes Europeen

Certainteed Gypsum, Inc.

Sylvain Petigny

Samuel Marlin

Yves Boussant-Roux

David Langohr

Bernard Bouteiller

The invention relates to a plaster-based composition comprising nanometric boehmite and/or nanometric aluminium trihydroxide, this composition making it possible to obtain products having better dimensional stability at high and in particular at very high temperature. The invention also relates to the method of obtaining the products, and the products produced.

Composition for plasterboards and products obtained

The invention relates to a fused grit having the following chemical analysis, in wt %: ZrO+HfO: 38.0-46.0%; AlO: the remainder up to 100%; SiO: 0.20-0.60%; YO: 0.45 to 0.70%; TiO: 1.00 to 2.00%; other oxides: &#x3c;1.00%, the ratio of YO/SiObeing 0.80 to 2.00, and the tetragonal phase being 60 to 90% of the weight of the zirconia, the remainder being in monoclinic form.

Molten grains of alumina-zirconia

A coated grain is provided with a fused base grain at least partially covered with a coating that includes silica. The base grain includes more than 40% of alumina as a percentage by weight based on the weight of the base grain.

Fused and coated silica grains

The invention relates to molten grains having the following chemical composition in wt % in terms of oxides: AlO: balance to 100%; ZrO+HfO: 16-24%; MgO in an amount such that the weight ratio (ZrO+HfO)/MgO is between 25 and 65; other species: 0-2%. The grains can be used as abrasive grains.

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Velleron, France

Sylvain Petigny