Abstract: A colloidal dispersion for chemical mechanical polishing comprising: (a) an abrasive component; and (b) from about 0.05% to about 10% by weight of the abrasive component, a water-soluble amphoteric polymer comprising at least one macromolecular chain B and a part A bonded to a single end of the at least one macromolecular chain B, wherein the macromolecular chain B is derived from one or more ethylenically unsaturated monomers having quaternary ammonium groups or inium groups, and wherein the part A is a polymeric or nonpolymeric group comprising at least one anionic group; wherein the dispersion has a pH of between about 1.5 and about 6. The colloidal dispersion is capable of polishing a substrate comprising silicon nitride and silicon oxide with a reverse selectivity ratio of at least about 27, typically at least 50 the reverse selectivity ratio being the ratio of the rate of removal of the silicon nitride to the rate of removal of the silicon oxide.

Abstract: Catalyst compositions include finely divided nanoscale particles of at least one supported oxide selected from among zirconium oxide, titanium oxide or a mixed zirconium/titanium oxide deposited onto an alumina-based or aluminum-oxyhydroxide-based support, wherein, after calcination for 4 hours at 900° C., the at least one support oxide is in the form of nanoscale particles deposited onto the support, the size of said particles being at most 10 nm when the at least one supported oxide is based is zirconium oxide and being at most 15 nm when the at least one supported oxide is titanium oxide or a mixed zirconium/titanium oxide; such catalyst compositions are especially useful for the selective reduction of NOx.

Abstract: Catalyst compositions include finely divided nanoscale particles of at least one supported oxide, based on a zirconium oxide, a titanium oxide or a mixed zirconium/titanium oxide deposited onto a silica based support, wherein, after calcination for 4 hours at 900° C., the supported oxide is in the form of nanoscale particles deposited onto the support, the size of the particles being at most 5 nm when the at least one supported oxide is based on a zirconium oxide, being at most 10 nm when the at least one supported oxide is based on a titanium oxide and being at most 8 nm when the at least one supported oxide is based on a mixed zirconium/titanium oxide; such catalyst compositions are especially useful for the selective reduction of NOx.

Abstract: A colloidal dispersion for chemical mechanical polishing comprising: (a) an abrasive component; and (b) from about 0.05% to about 10% by weight of the abrasive component, a water-soluble amphoteric polymer comprising at least one macromolecular chain B and a part A bonded to a single end of the at least one macromolecular chain B, wherein the macromolecular chain B is derived from one or more ethylenically unsaturated monomers having quaternary ammonium groups or inium groups, and wherein the part A is a polymeric or nonpolymeric group comprising at least one anionic group; wherein the dispersion has a pH of between about 1.5 and about 6. The colloidal dispersion is capable of polishing a substrate comprising silicon nitride and silicon oxide with a reverse selectivity ratio of at least about 27, typically at least 50 the reverse selectivity ratio being the ratio of the rate of removal of the silicon nitride to the rate of removal of the silicon oxide.

Abstract: A colloidal dispersion for chemical mechanical polishing comprising: (a) an abrasive component; and (b) from about 0.05% to about 10% by weight of the abrasive component, a water-soluble amphoteric polymer comprising at least one macromolecular chain B and a part A bonded to a single end of the at least one macromolecular chain B, wherein the macromolecular chain B is derived from one or more ethylenically unsaturated monomers having quaternary ammonium groups or inium groups, and wherein the part A is a polymeric or nonpolymeric group comprising at least one anionic group; wherein the dispersion has a pH of between about 1.5 and about 6. The colloidal dispersion is capable of polishing a substrate comprising silicon nitride and silicon oxide with a reverse selectivity ratio of at least about 27, typically at least 50 the reverse selectivity ratio being the ratio of the rate of removal of the silicon nitride to the rate of removal of the silicon oxide.

Abstract: Compositions useful for treating the exhaust gases of diesel engines contain zirconium oxide, silicon oxide and at least one oxide of at least one element M selected from among titanium, aluminum, tungsten, molybdenum, cerium, iron, tin, zinc, and manganese, in the following mass proportions of these different elements: silicon oxide: 5%-30%; M-element oxide: 1%-20%; the balance being zirconium oxide; such compositions also have an acidity, as measured by the methylbutynol test, of at least 90% and are prepared by placing a zirconium compound, a silicon compound, at least one M-element compound and a basic compound in a liquid medium, thereby generating a precipitate, maturing the precipitate in a liquid medium and separating and calcining the precipitate.

Abstract: Suspensions of cerium oxide particles in which the particles (secondary particles) have an average size not exceeding 200 nm, such secondary particles being comprised of primary particles having an average size not exceeding 100 nm with a standard deviation having a value not exceeding 30% of the value of this average size, are prepared from a solution of a cerium-III salt, including cerium IV or hydrogen peroxide, which is contacted with a base in the presence of nitrate ions and in an inert atmosphere; the medium thus obtained is subjected to a thermal processing in an inert atmosphere, then acidified and scrubbed and the powder is obtained by drying and calcining of the suspension, which suspension and powder are useful for polishing applications.

Abstract: Colloidal dispersions of inorganic particles in a liquid phase include ampholytic copolymers containing at least one macromolecular chain B and a moiety A bonded to a single end thereof and in which the macromolecular chain B includes cationic units Bc, deriving from cationic monomers Bc and the moiety A is a polymeric or non-polymeric group containing at least one anionic or potentially anionic group; such dispersions may have a positive zeta potential within a pH ranging from 1 to 11.

Abstract: Suspensions of cerium oxide particles, well suited for polishing applications, the particles (secondary particles) of which have an average size of at most 200 nm, these secondary particles are formed from primary particles whose average size measured by TEM is at most 150 nm with a standard deviation of at most 30% of the value of this average size, and for which the ratio of the average size measured by TEM to the average size measured by BET is at least 1.5. Such suspensions are prepared from solutions of a cerium III salt, comprising a colloidal dispersion of cerium IV, which are contacted, in the presence of nitrate ions and under an inert atmosphere, with a base, and the medium obtained is subjected to a thermal treatment under an inert atmosphere and then acidified and washed.

Abstract: Catalyst compositions include finely divided nanoscale particles of at least one supported oxide selected from among zirconium oxide, titanium oxide or a mixed zirconium/titanium oxide deposited onto an alumina-based or aluminum-oxyhydroxide-based support, wherein, after calcination for 4 hours at 900° C., the at least one support oxide is in the form of nanoscale particles deposited onto the support, the size of said particles being at most 10 nm when the at least one supported oxide is based is zirconium oxide and being at most 15 nm when the at least one supported oxide is titanium oxide or a mixed zirconium/titanium oxide; such catalyst compositions are especially useful for the selective reduction of NOx.

Abstract: Catalyst compositions include finely divided nanoscale particles of at least one supported oxide, based on a zirconium oxide, a titanium oxide or a mixed zirconium/titanium oxide deposited onto a silica based support, wherein, after calcination for 4 hours at 900° C., the at least one supported oxide is in the form of nanoscale particles deposited onto the support, the size of the particles being at most 5 nm when the at least one supported oxide is based on a zirconium oxide, being at most 10 nm when the at least one supported oxide is based on a titanium oxide and being at most 8 nm when the at least one supported oxide is based on a mixed zirconium/titanium oxide; such catalyst compositions are especially useful for the selective reduction of NOx.

Abstract: Compositions based on zirconium oxide, including 1 to 20% yttrium oxide, 1 to 30% tungsten oxide and the balance zirconium oxide, have a specific surface area of at least 40 m2/g after calcination at 700° C. for 4 hours and an acidity measured by the methylbutynol test of at least 90%, and are useful as catalyst or catalyst supports, especially for the treatment of motor vehicle exhaust gases.

Abstract: Colloidal dispersions of inorganic particles in a liquid phase include ampholytic copolymers containing at least one macromolecular chain B and a moiety A bonded to a single end thereof and in which the macromolecular chain B includes cationic units Bc, deriving from cationic monomers Bc and the moiety A is a polymeric or non-polymeric group containing at least one anionic or potentially anionic group; such dispersions may have a positive zeta potential within a pH ranging from 1 to 11.

Abstract: Compositions useful for treating the exhaust gases of diesel engines contain zirconium oxide, silicon oxide and at least one oxide of at least one element M selected from among titanium, aluminum, tungsten, molybdenum, cerium, iron, tin, zinc, and manganese, in the following mass proportions of these different elements: silicon oxide: 5%-30%; M-element oxide: 1%-20%; the balance being zirconium oxide; such compositions also have an acidity, as measured by the methylbutynol test, of at least 90% and are prepared by placing a zirconium compound, a silicon compound, at least one M-element compound and a basic compound in a liquid medium, thereby generating a precipitate, maturing the precipitate in a liquid medium and separating and calcining the precipitate.

Abstract: A colloidal dispersion for chemical mechanical polishing comprising: (a) an abrasive component; and (b) from about 0.05% to about 10% by weight of the abrasive component, a water-soluble amphoteric polymer comprising at least one macromolecular chain B and a part A bonded to a single end of the at least one macromolecular chain B, wherein the macromolecular chain B is derived from one or more ethylenically unsaturated monomers having quaternary ammonium groups or inium groups, and wherein the part A is a polymeric or nonpolymeric group comprising at least one anionic group; wherein the dispersion has a pH of between about 1.5 and about 6. The colloidal dispersion is capable of polishing a substrate comprising silicon nitride and silicon oxide with a reverse selectivity ratio of at least about 27, typically at least 50 the reverse selectivity ratio being the ratio of the rate of removal of the silicon nitride to the rate of removal of the silicon oxide.

Abstract: Suspensions of cerium oxide particles in which the particles (secondary particles) have an average size not exceeding 200 nm, such secondary particles being comprised of primary particles having an average size not exceeding 100 nm with a standard deviation having a value not exceeding 30% of the value of this average size, are prepared from a solution of a cerium-III salt, including cerium IV or hydrogen peroxide, which is contacted with a base in the presence of nitrate ions and in an inert atmosphere; the medium thus obtained is subjected to a thermal processing in an inert atmosphere, then acidified and scrubbed and the powder is obtained by drying and calcining of the suspension, which suspension and powder are useful for polishing applications.