Ultrafine particles and production method thereof
AssigneesResearch Development Corporation of Japan, Shun-ichiro Tanaka
InventorsShun-ichiro Tanaka, Bing She Xu
Life of this patent
Estimating the term…
Abstract
An electron beam of more than 1.times.10.sup.19 e/cm.sup.2 .multidot.sec is irradiated to metastable metal oxide particles such as .theta.-Al.sub.2 O.sub.3 particles or the like disposed on an amorphous carbon film. A phase transformation or the like of the metastable metal oxide particles is occurred by the electron beam irradiation. Thus, stable metal oxide ultrafine particles such as an .alpha.-Al.sub.2 O.sub.3 ultrafine particle 2 whose diameter is more tiny than the metastable metal oxide particles used, and a metal ultrafine particle composed of an oxide such as Al ultrafine particles are produced.
Claims10
An ultrafine powder comprising at least one selected from the group consisting of stable ultrafine particles of a metal oxide and nanoparticles of a metal which is a component of the metal oxide,
- wherein the ultrafine particles and the nanoparticles are produced from metastable particles of the metal oxide by irradiating an electron beam in a vacuum to form the ultrafine powder.
A method for producing an ultrafine powder comprising at least one selected from the group consisting of ultrafine stable particles of a metal oxide and nanoparticles of a metal which is a component metal of the metal oxide, comprising a step of irradiating an electron beam having an intensity of more than 10.sup.19 e/cm.sup.2 .multidot.sec in a vacuum to metastable particles of the metal oxide, the metastable particles being disposed on an amorphous carbon film.
A preferentially growing body of ultrafine particles of a stable metal oxide,
- wherein the ultrafine particles are grown in a definite crystal direction of the ultrafine particles to form the preferentially growing body.
A method for producing a preferentially growing body of ultrafine particles comprising the steps of:
- disposing metastale metal oxide particles on an amorphous carbon film,
- irradiating preliminary an electron beam having an intensity of more than 10.sup.19 e/cm.sup.2 .multidot.sec to a portion of the amorphous carbon film surrounding the metastable metal oxide particles,
- irradiating an electron beam having an intensity of more than 10.sup.19 e/cm.sup.2 .multidot.sec in a vacuum to the metastable metal oxide particles of the metal oxide to the metastable metal oxide particles to form stable metal oxide ultrafine particles, and
- irradiating continuously to the stable metal oxide particles to form a preferentially growing body which grows in an definite crystal direction of the metal oxide ultrafine particles.
Dependencies are inferred from the claim text.