Method of making a composite powder comprising nanocrystallites embedded in an amorphous phase
AssigneeFried.Krupp GmbH
InventorsHans Grewe, Wolfgang Schlump
Life of this patent
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Abstract
A process for the production of a powder having a nanocrystalline structure from powders of at least two materials of the groups including metals, metallic compounds, and ceramic materials, in a composition which tends to develop an amorphous phase. The starting powders are subjected to high stresses of at least 12 G in a neutral or reducing atmosphere at about 20.degree. C. until there are no crystallites larger than about 10 nm.
Claims19
A process for producing a powder, comprising the steps of:
- mixing powders of at least two different ceramics, in a ratio adapted to form at least one amorphous phase;
- and
- subjecting the mixed powders to mechanical stresses of at least 12 G in a neutral or reducing atmosphere at about 20.degree. C. until there are no crystallites larger than about 10 nm as determined by transmission electron microscopy, to produce powder particles having unreactive exterior surfaces and comprising at least one amorphous phase in which said crystallites not larger than about 10 nm are embedded.
A process for producing a powder, comprising the steps of:
- mixing, in a ratio adapted to form at least one amorphous phase, a first powder essentially composed of at least one element from the group consisting of Y, Ti, Zr, Hf, Nb, Mo, Ta and W in elemental form or as a compound also containing at least one element selected from the group consisting of Si, Ge, B, O, N and C, with a second powder essentially composed of at least one element from the group consisting of V, Cr, Mn, Fe, Co, Ni, Cu and Pd in elemental form or as a compound also containing at least one element selected from the group consisting of Si, Ge, B, O, N and C;
- and
- subjecting the mixed powders to mechanical stresses of at least 12 G until there are no crystallites larger than about 10 nm as determined by transmission electron microscopy, to produce powder particles having unreactive exterior surfaces and comprising at least one amorphous phase in which said crystallites not larger than about 10 nm are embedded.
A process for producing a powder, comprising the steps of:
- mixing powders of at least two different metals, in a ratio adapted to form at least one amorphous phase;
- and
- subjecting the mixed powders to mechanical stresses of at least 12 G in a neutral or reducing atmosphere at about 20.degree. C. until there are no crystallites larger than about 10 nm as determined by transmission electron microscopy, to produce powder particles having unreactive exterior surfaces and comprising at least one amorphous phase in which said crystallites not larger than about 10 nm are embedded.
A process for producing a powder, comprising the steps of:
- mixing powders of at least two different compounds having metallic characteristics in a ratio adapted to form at least one amorphous phase;
- and
- subjecting the mixed powders to mechanical stresses of at least 12 G in a neutral or reducing atmosphere at about 20.degree. C. until there are no crystallites larger than about 10 nm as determined by transmission electron microscopy, to produce powder particles having unreactive exterior surfaces and comprising at least one amorphous phase in which said crystallites not larger than about 10 nm are embedded.
Dependencies are inferred from the claim text.