3 results about "Silicon nanocrystal" patented technology

The present invention provides an ultraviolet shielding agent containing spherical silicon nanocrystals of a predetermined particle size. The agent contains spherical silicon nanocrystals with a peak particle size distribution between 40 nm and 200 nm. Particularly, it is preferable to include silicon nanocrystals between 60 nm and less than 90 nm. The agent has an ultraviolet transmittance of 10% or less at 400 nm and below, a visible light transmittance of 50% or more at 500 nm and above, and a haze value of 40% or more at 500 nm and below. The ultraviolet shielding agent is in the form of a dispersion or film containing silicon nanocrystals with a controlled particle size distribution.

A method for preparing an aluminum-based composite material in which silicon carbide nanocrystals and micron-sized particles are layered is disclosed. This invention addresses the problems of uncontrollable reinforcement distribution, difficulty in oriented whisker alignment, and difficulty in achieving dense impregnation of preforms under high ceramic content conditions in existing aluminum-based composite materials. The steps of this invention include: Step 1, acid washing of the whiskers and particles; Step 2, preparation of a slurry; Step 3, freeze casting to form a preform; Step 4, vacuum freeze drying; Step 5, sintering of the preform; and Step 6, extrusion impregnation of the aluminum-based composite material. This invention belongs to the field of aluminum-based composite material preparation technology.

The application relates to a high-performance composite negative electrode material based on a bulk silicon nanocrystal and a preparation and application thereof, and the preparation method of the negative electrode material comprises the following steps: (1) weighing silicon monoxide powder, a lithium source additive and a heat conduction network material, grinding and mixing to obtain a precursor mixture; (2) placing the precursor mixture on a carrier, carrying out a high-temperature disproportionation reaction, and cooling to room temperature to obtain modified silicon monoxide composite powder, namely a target product. Compared with the prior art, the application can effectively relieve mechanical stress caused by volume expansion of the nanocrystal in a cycle process, avoid particle rupture, and significantly improve the cycle stability of the material and the like.