A hafnium compound-containing sol-gel liquid contains an alcohol as a solvent and a hafnium compound as a hafnia source, in which the hafnium compound-containing sol-gel liquid contains one or two or more elements M selected from the group consisting of Zr, Ti, and Nb, a mass ratio W.sub.M/W.sub.Hf of a content W.sub.M of the elements M to a content W.sub.Hf of Hf as a metal component is within a range of 0.2% or more and 5.0% or less. A hafnia-containing film containing hafnia (HfO.sub.2) and one or two or more elements M selected from the group consisting of Zr, Ti, and Nb, and in which a mass ratio W.sub.M/W.sub.HfO2 of a content W.sub.M of the elements M to a content W.sub.HfO2 of the HfO.sub.2 is within a range of 0.05% or more and 5.0% or less.

Articles of wear comprises iron oxide colloidal nanocrystals arranged within chains are described. The chains of nanocrystals display a color that is determined by a strength of a magnetic field applied to the chains of nanocrystals, wherein the color is maintained when the magnetic field is removed.

The present invention relates to a method for producing a colloid comprising functionalized liquid colloidal particles. The Invention also relates to such a colloid and to the uses thereof.

Core-shell type metal oxide particles each include: a core containing metal oxide particles that have an average primary particle diameter of 3-100 nm; and a shell containing metal oxide particles that have an average primary particle diameter of 1-7 nm and that cover the core surfaces. The average primary particle diameters have a relationship of (metal oxide particles of the cores)>(metal oxide particles of the shells). When component (a) is titanium oxide and component (b) is a metal oxide other than titanium oxide, the cores are formed of particles including component (a) or a combination of component (a) and component (b), and the shells are formed of particles including component (b). The mass ratio of (metal oxide other than titanium oxide)/(titanium oxide) is in the range of 0.05-1.0.

The invention relates to a sol formulation which can be used to form a solar-control coating, in particular a coating that blocks UV and NIR radiation, comprising at least: one or more silica-based sol-gel matrix precursors, and doped tungsten bronze nanocrystals which are dispersed uniformly and individually in a protic solvent medium. The invention also relates to a method for forming a solar-control coating at the surface of a support using such a sol formulation, and also to a structure comprising at least one support, preferably a transparent support, having such a solar-control coating on at least one face thereof.

A zirconia sol that has a particle diameter D.sub.50 of 50 nm to 250 nm and a proportion X of at least 40% is obtained by the following procedure. (Procedure) A transmission electron microscope image that includes at least 20 isolated particles is obtained. The following operations (1) through (5) are performed on each of the isolated particles. (1) A circumscribed circle and an inscribed circle having the same center as the circumscribed circle are obtained. (2) The ratio of the diameter of the obtained circumscribed circle and the diameter of the obtained inscribed circle is determined. (3) The ratio is determined for all of the isolated particles in the transmission electron microscope image. (4) The number of isolated particles A where the ratio is at least 2.0 is counted. (5) The proportion X of the number of isolated particles A to the total number of isolated particles is determined.