摘要:
A deformed ultra fine grain is comprised of a spherical body and a tail-like projection projecting from the surface of the spherical body. The tail-like projection exhibits a separating effect on the adjacent deformed ultra fine grains and therefore, aggregation of the ultra fine grains is avoided. Bulk quantities of the deformed ultra fine grains are produced by evaporating a metal by a plasma arc in a controlled atmosphere having a gas that combines with the material of the spherical body to form the tail-like projection.
摘要:
Quasi-crystalline aluminum alloy ultrafine particles are produced by a gas-phase reaction and consist of at least one alloy element from the group of V, Cr, Mn, Fe, Co, Ni, Cu and Pd, for example palladium (Pd) in an amount represented by 20 atomic %.ltoreq.Pd.ltoreq.30 atomic %, and the balance of aluminum. Palladium has a catalyst power, and the ultrafine particles have a large specific surface area, because they have a particle size d.ltoreq.200 nm. Such ultrafine particles have a high catalytic activity in a methanol decomposing reaction and also have a good retention of catalytic activity.
摘要:
Ultrafine amorphous metal particles which combine the properties of ultrafine particles with those of an amorphous alloy and a method for the production thereof are disclosed. The ultrafine amorphous metal particles are produced by a method which comprises discharging a plasma arc against a raw metal capable of forming a carbide in a reaction gas using an inert gas as a main component thereof and containing a hydrocarbon gas, and allowing the metal which has been consequently vaporized to contact the reaction gas which has been consequently converted into a plasma, thereby inducing formation of a solid solution of carbon atoms in the vaporized metal and quenching the solid solution in the reaction gas to confer an amorphous structure thereon. As the raw metal, at least one metal selected from the group consisting of Fe, Mo, Nb, Ta, Ti, Zr, Al, Si, and Cr is preferably used. By this method are obtained ultrafine amorphous metal particles which comprise the metal mentioned above, possess at least 50% by volume of an amorphous phase, and have particle diameters of not more than 500 nm.
摘要:
Ultrafine particles of aluminum nitride having a morphologically anisotropic structure of columns, plates, or whiskers such that the ratio of thickness or width to length or the ratio of thickness to width or length of particle is not less than 1 are produced by thermally melting a binary alloy of metallic aluminum and a rare earth element in a nitriding atmosphere containing nitrogen. By this method are produced composite ultrafine particles which substantially comprise ultrafine particles of aluminum nitride having the morphologically anisotropic structure and ultrafine particles of the rare earth nitride which functions as a sintering auxiliary therefor. The composite ultrafine particles or an aggregate thereof are usable as a raw material for the production of a sintered article, a reinforcing material for various metal-based composite materials, a blast powder, and the like.
摘要:
A structural member is produced using starting powder consisting of composite particulates each containing AlN grain within its surface covered by an Al layer of a single crystal structure, and Al alloy particulates of a single crystal structure, and then by sintering the Al layers of the composite particulates with the Al alloy particulates. The Al layers and the Al alloy particulates of the single crystal structure have no dislocation fault, crystal grain boundary. etc., produced therein, and for this reason, they have a low chemical activity. Therefore, the Al layers and the like have a characteristic that they are extremely difficult to oxidize. This ensures that the Al layers and the Al alloy particulates can be reliably sintered to achieve the densification of the resulting structural member.
摘要:
A catalyst for methanol reforming which consists of an alloy represented by the general formula TM, wherein T is at least one element selected from the group consisting of Ti, Zr, Hf, Y, Nb and Zn; and M is at least one element selected from the group consisting of elements (Cu, Ag and Au) belonging to group IB of the periodic table and elements (Fe, Co, Ni, Ru, Rh, Pd, Os, Ir and Pt) belonging to group VIII of the periodic table, said alloy having a surface comprising an oxide including the element T and, dispersed therein, fine metal particles composed of the element M. The catalyst is produced by preparing an alloy having an amorphous phase and/or a microcrystalline phase from a molten composition of TM, and subsequently heating the alloy at 50.degree. to 700.degree. C. in an oxidizing atmosphere or an atmosphere like that in which methanol reforming is performed. Using the catalyst, methanol reforming can be efficiently performed at relatively low temperatures.
摘要:
Ultrafine whiskery or columnar ceramic particles, a method for producing the ultrafine particles, and a sintered article obtained by sintering the ultrafine ceramic particles are disclosed. The ultrafine ceramic particles are produced by thermally melting a matrix alloy of a composition of Al--M.sup.1, wherein M.sup.1 stands for at least one metallic element selected from the group consisting of Cr, Co, and Fe, or Al--M.sup.1 --M.sup.2, wherein M.sup.2 stands for at least one metallic element selected from the group consisting of Au, Cu, Dy, Er, Ga, Ge, Gd, Hf, Ho, Lu, Mn, Mo, Nb, Nd, Ni, Pr, Re, Sb, Sc, Si, Sn, Ta, Tb, Ti, Tm, V, W, Y, Zn, or Zr, in a nitriding atmosphere containing nitrogen and causing the vaporized raw material to react with the nitrogen in the atmosphere. By this method, ultrafine composite particles or a mixture comprising ultrafine whiskery or columnar aluminum nitride particles and ultrafine particles of the metal, the intermetallic compound of the metal with aluminum, and the nitride ceramic of the metal are produced. The ultrafine particles thus obtained find extensive utility as sintering materials and dispersion materials, for example.
摘要:
Deposition of a hard film of Ti-Si-N composite material on a substrate is carried out by using a source of evaporation possessing a composition of Ti.sub.a Si.sub.b (wherein "a" and "b" stand for atomic percentages respectively falling in the ranges of 75 at % .ltoreq.a.ltoreq.85 at % and 15 at %.ltoreq.b.ltoreq.25 at %, providing a+b=100 at %). Deposition is effected by a sputtering process or ion plating process in an atmosphere of an inert gas containing a nitrogen-containing reaction gas while controlling the feed rate of the reaction gas into a chamber in such a manner that the partial pressure of nitrogen is kept constant or varied continuously or stepwise. By this method there can be obtained a film having fine TiN crystalline particles uniformly dispersed in the matrix phase of Ti-Si amorphous metal or a film of functionally gradient structure in which the ratio of fine TiN crystalline particles dispersed in the matrix phase increases continuously or stepwise in the direction of thickness of the film.
摘要翻译:通过使用具有TiaSib组成的蒸发源(其中“a”和“b”表示分别落在75的范围内的原子百分比),将Ti-Si-N复合材料的硬膜沉积在基底上 at% = a = 85 at%和15 at% = b = 25 at%,提供+ b = 100 at%)。 在含有含氮反应气体的惰性气体的气氛中通过溅射法或离子镀法进行沉积,同时将反应气体的进料速率控制在室内,使得氮的分压保持恒定 或连续或逐步变化。 通过该方法可以获得均匀分散在Ti-Si非晶态金属的基体相中的细TiN结晶粒子的膜或其中分散在基体相中的细TiN结晶粒子的比例连续增加的功能梯度结构的膜,或 在膜的厚度方向上逐步地。
摘要:
Deposition of a hard film of Ti--Si--N composite material on a substrate is carried out by using a source of evaporation possessing a composition of Ti.sub.a Si.sub.b (wherein "a" and "b" stand for atomic percentages respectively falling in the ranges of 75 at %.ltoreq.a.ltoreq.85 at % and 15 at %.ltoreq.b.ltoreq.25 at %, providing a+b=100 at %). Deposition is effected by a sputtering process or ion plating process in an atmosphere of an inert gas containing a nitrogen-containing reaction gas while controlling the feed rate of the reaction gas into a chamber in such a manner that the partial pressure of nitrogen is kept constant or varied continuously or stepwise. By this method, there can be obtained a film having fine TiN crystalline particles uniformly dispersed in the matrix phase of Ti--Si amorphous metal or a film of functionally gradient structure in which the ratio of fine TiN crystalline particles dispersed in the matrix phase increases continuously or stepwise in the direction of thickness of the film.
摘要翻译:通过使用具有TiaSib组成的蒸发源(其中“a”和“b”表示分别落在75的范围内的原子百分比),将Ti-Si-N复合材料的硬膜沉积在基板上 at% = a = 85 at%和15 at% = b = 25 at%,提供+ b = 100 at%)。 在含有含氮反应气体的惰性气体的气氛中通过溅射法或离子镀法进行沉积,同时将反应气体的进料速率控制在室内,使得氮的分压保持恒定 或连续或逐步变化。 通过该方法,可以得到均匀分散在Ti-Si非晶态金属的基体相中的细TiN结晶粒子的膜或功能梯度结构的膜,其中分散在基体相中的细TiN结晶粒子的比率连续增加 或者在薄膜的厚度方向上逐步。
摘要:
An aluminum-based alloy having the general formula Al.sub.x L.sub.y M.sub.z (wherein L is Mn or Cr; M is Ni, Co, and/or Cu; and x, y, and z, representing a composition ratio in atomic percentages, satisfy the relationships x+y+z=100, 75.ltoreq.x.ltoreq.95, 2.ltoreq.y.ltoreq.15, and 0.5.ltoreq.z.ltoreq.10) having a metallographic structure comprising a quasi-crystalline phase possesses high strength and high rigidity. In order to enhance the ductility and toughness of the aluminum-based alloy, the atomic percentage of M may be further limited to 0.5.ltoreq.z.ltoreq.4, and more preferably to 0.5.ltoreq.z.ltoreq.3. The aluminum-based alloy is useful as a structural material for aircraft, vehicles and ships, and for engine parts; as material for sashes, roofing materials, and exterior materials for use in construction; or as materials for use in marine equipment, nuclear reactors, and the like.