A method of making a titanium dioxide nanowire array includes contacting a substrate with a solvent comprising a titanium (III) precursor, an acid, and an oxidant while microwave heating the solvent, thereby forming a hydrogen titanate H2Ti2O5.H2O nanowire array. The hydrogen titanate nanowire array is annealed to form a titanium dioxide nanowire array. The substrate is seeded with titanium dioxide before starting the hydrothermal synthesis of the hydrogen titanate nanowire array. The titanium dioxide nanowire array is loaded with a platinum group metal to form an exhaust gas catalyst. The titanium dioxide nanowire array can be used to catalyze oxidation of combustion exhaust.

A method of making a titanium dioxide nanowire array includes contacting a substrate with a solvent comprising a titanium (III) precursor, an acid, and an oxidant while microwave heating the solvent, thereby forming a hydrogen titanate H2Ti2O5.H2O nanowire array. The hydrogen titanate nanowire array is annealed to form a titanium dioxide nanowire array. The substrate is seeded with titanium dioxide before starting the hydrothermal synthesis of the hydrogen titanate nanowire array. The titanium dioxide nanowire array is loaded with a platinum group metal to form an exhaust gas catalyst. The titanium dioxide nanowire array can be used to catalyze oxidation of combustion exhaust.

The present invention relates to a composite material including a porous titania thin film and a preparation method therefor. A composite material according to the present invention allows for a simple thin film formation process because of the use of cellulose crystals, makes it easy to control the structure of the titanium dioxide thin film provided therefor, has a large specific area, and is superior in terms of scratch resistance and photoactivity, thus finding useful applications in the various fields utilizing titanium dioxide as a photocatalyst.

The present invention relates to a composite material including a porous titania thin film and a preparation method therefor. A composite material according to the present invention allows for a simple thin film formation process because of the use of cellulose crystals, makes it easy to control the structure of the titanium dioxide thin film provided therefor, has a large specific area, and is superior in terms of scratch resistance and photoactivity, thus finding useful applications in the various fields utilizing titanium dioxide as a photocatalyst.

A turbine engine part coated in at least a first ceramic layer forming a thermal barrier and including a ceramic material with first ceramic fibers dispersed in the first layer. The first layer may have a chemical composition gradient between a material for forming a thermal barrier and a material for providing protection against calcium and magnesium aluminosilicates, which is present at a greater content in an outer zone of the first layer, and/or the first layer may be porous and may present a porosity gradient such that an outer portion of the first layer presents lower porosity.

A turbine engine part coated in at least a first ceramic layer forming a thermal barrier and including a ceramic material with first ceramic fibers dispersed in the first layer. The first layer may have a chemical composition gradient between a material for forming a thermal barrier and a material for providing protection against calcium and magnesium aluminosilicates, which is present at a greater content in an outer zone of the first layer, and/or the first layer may be porous and may present a porosity gradient such that an outer portion of the first layer presents lower porosity.

A process for treating a substrate made of stone material, preferably in the form of slabs, is provided which process improves the mechanical, thermal and catalytic properties of the substrate. The process includes applying a protective coating to the outer surface of the substrate made of stone material and, to improve adhesion of the protective coating to the outer surface of the substrate, preliminarily subjecting the substrate to one or more pre-treatment steps that eliminate or reduce the presence of pollutants and porosity on the surface of the substrate. The pre-treatment of the substrate made of stone material comprises at least one step of treatment under vacuum conditions inside an autoclave, preferably under pressure conditions lower than 10.sup.2 mbar. Then, after having brought the substrate back to ambient pressure, it is possible to apply and effectively adhere the protective coating to the surface of the stone material.

A process for treating a substrate made of stone material, preferably in the form of slabs, is provided which process improves the mechanical, thermal and catalytic properties of the substrate. The process includes applying a protective coating to the outer surface of the substrate made of stone material and, to improve adhesion of the protective coating to the outer surface of the substrate, preliminarily subjecting the substrate to one or more pre-treatment steps that eliminate or reduce the presence of pollutants and porosity on the surface of the substrate. The pre-treatment of the substrate made of stone material comprises at least one step of treatment under vacuum conditions inside an autoclave, preferably under pressure conditions lower than 10.sup.2 mbar. Then, after having brought the substrate back to ambient pressure, it is possible to apply and effectively adhere the protective coating to the surface of the stone material.

A method for enhancing mechanical properties of sintered, zirconia ceramic bodies and zirconia ceramic dental restorations is provided. A porous or pre-sintered stage of a ceramic body may be treated with a tantalum-containing composition prior to sintering. Alternatively, zirconia ceramic powder may be coated with a tantalum-containing composition prior to forming a shaped ceramic body. After sintering, the resulting ceramic bodies have enhanced mechanical properties, such as greater fracture toughness, without a significant decrease in optical properties.

A method for enhancing mechanical properties of sintered, zirconia ceramic bodies and zirconia ceramic dental restorations is provided. A porous or pre-sintered stage of a ceramic body may be treated with a tantalum-containing composition prior to sintering. Alternatively, zirconia ceramic powder may be coated with a tantalum-containing composition prior to forming a shaped ceramic body. After sintering, the resulting ceramic bodies have enhanced mechanical properties, such as greater fracture toughness, without a significant decrease in optical properties.