JPH0213002B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing alloy powder, and more particularly to a method for producing alloy powder by mechanical pulverization. Metal powders containing alloys are widely used as pigments for paint additives and raw materials for powder metallurgy, and are usually produced by distillation, molten metal injection, molten metal injection + wet pulverization, foil + mill pulverization + air flow pulverization, etc. There is. However, although the distillation method, molten metal injection method, etc. have the advantage of producing fine granular powder, they have the disadvantage of requiring a large amount of high-temperature thermal energy.
On the other hand, known mechanical pulverization methods include the Hametag method, in which aluminum is pulverized in a stream of inert gas using a dry ball mill, and the Hall method, in which aluminum is pulverized using a wet ball mill.
Various methods have been proposed for applying this method to various alloys or metals, but the powder obtained is a scaly powder, which has the disadvantage that it cannot be used depending on the purpose of use. As a method of obtaining granular powder by mechanical crushing,
Japanese Patent Publication No. 49-2675 discloses a method of embrittling Ni-Ti alloy by immersing it in acid and pulverizing it, and a method of embrittling it with nascent hydrogen and pulverizing it. The resulting powder is quite coarse, at most 87% below 50 meshes, and has a fairly wide particle size distribution. The present invention has a narrow particle size distribution width due to mechanical pulverization.
Another object of the present invention is to provide a method for efficiently producing fine granular powder. As a result of intensive research to achieve the above object, the present inventors have found that the atomic size factor of the additive metal is greater than a certain range with respect to the base metal, and the metal has an intermediate phase. By mechanically pulverizing an alloy that had not been used in the past due to its brittleness, the inventors discovered that it could be pulverized extremely efficiently and that it could be used in the same way as conventional alloy powders, thus completing the present invention. In _the present invention, _the following general formula [ _] [ ₍ γ An alloy containing at least one type of additive metal with an atomic size factor of 13% or more and having an intermediate phase is machined _. This is a method for producing alloy powder, characterized by pulverizing it using a pulverizer. In _the present invention, _the alloy to be mechanically pulverized has the following general formula [ _{( γ B} : An alloy containing at least one type of additive metal whose atomic size factor relative to the base metal, expressed as the atomic radius of the base metal [Å]), is 13% or more, and has an intermediate phase; When more than one kind of additive metal is contained, the relationship between the additive metals is expressed by the _following general formula [] [( _{γ X} ~ γ _X1 )/γ It is preferable that the atomic size factor expressed as: atomic radius of the metal with a large content [Å] γ _X1 ; atomic radius of the metal with a smaller content than _γ The intermediate phase of the present invention is a different phase having an intermediate component that occurs as an exception to the phase of each of the two components of the alloy, and that occurs between the base metal and the additive metal. It is a mesophase solid solution with a composition intermediate to that of metals. Examples of these alloys include 3.5 to 40% Mg, and
Alloy of Zn, Mg0.5-40%, Ni0.8-30%, remaining Zn alloy, Mg0.5-40%, Ti0.5-7%, Al0.01-5
%, alloy with residual Zn, Sb55~65%, alloy with residual Zn,
Alloy with Sb30~50%, Cr1% or less remaining Zn, Zn2.4% or less, Al37~48% remaining Ni, Si20% or less, Al17
Examples include alloys with a residual Ni content of ~38%. Atomic size factors between metals are shown in Table 1. If the added metal consists only of metals with an atomic size factor of less than 13% relative to the base metal,
In addition, even if 13% or more of metal is added, if it does not have an intermediate phase as a primary crystal, it becomes malleable and although it is possible to obtain a scaly powder by mechanical crushing,
It is difficult and undesirable to obtain the desired granular powder. In the present invention, the alloy is pulverized using a conventionally known mechanical pulverizer. For example, Jyo Crusher, Yare Restrictor, Cone Crusher, Edge Runner Roll Crusher,
Crusher such as rotary crusher, hammer crusher, ball mill, ring roller mill, etc.
Any pulverizer such as an impact pulverizer, stamp mill, jet mill, vibration mill, etc. can be used, and alloy powder of any particle size can be obtained by using two or more of these pulverizers in combination.
Specifically, the average particle size is
Crushed to 10 to 20 mm, the coarsely crushed material is crushed to an average particle size of approximately 1 mm using a Nara type crusher, and the medium crushed material is crushed to 325 mesh using an impact crusher such as a screen mill.
After pulverizing to 50% or more, the pulverized product can be easily pulverized to 10 to 30 μm using a jet mill. What is even more surprising is that even if these pulverizations are carried out in the atmosphere, hardly any oxides are produced, and therefore there is no risk of explosion due to rapid oxidation of the alloy powder. The present invention provides an alloy composition containing at least one type of additive metal having an atomic size factor of 13% or more with respect to the base metal, which could not be used at all due to its brittleness, and having an intermediate phase. By doing so, one of the known mechanical crushers
By using a species or a combination of two or more species,
The present invention provides a method for easily producing alloy powder having an average particle size of several micrometers to several tens of micrometers in the atmosphere, and is of extremely great industrial significance. The alloy powder of the present invention can be used as a pigment for paints, etc. Hereinafter, the present invention will be explained in more detail with reference to Examples. However, the present invention is not limited to the following examples. Example 1 Magnesium was added to zinc, Mg6.8% by weight,
After melting the residual Zn alloy and coarsely crushing the alloy with a Jio crusher (0.75KW manufactured by Yoshida Seisakusho),
The coarsely crushed material was pulverized using a Nara type pulverizer (manufactured by 1K.W. Nara Kikai). Then, the medium crushed material was crushed by an impact crusher (0.75K.
W. Hosokawa Micron) was used to pulverize twice, and the pulverized product was further finely pulverized using an air flow pulverizer (22K.W. manufactured by Nisso Engineering). The particle size distribution of the powder obtained as a result of two rounds of crushing with an impact crusher and with a pneumatic crusher is shown in Table 2. Examples 2 to 5 Alloy powders were produced using the same equipment as in Example 1 except that the alloy composition was changed. The results are shown in Table 2. Example 6 The crushability of various alloy compositions was investigated using the same equipment as in Example 1. The results are shown in Table 3.

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[Table] ○ mark in the table Mechanical crushing is easy
△: Mechanical pulverization is possible, but plastic deformation is observed in some parts, making pulverization difficult.
×: Plastically deformed and not suitable for mechanical crushing

Claims (1)

_[ Scope of Claims] 1 Based on the base _metal , the _following general formula [ _] [(γ Radius [Å] γ _B ; Represents the atomic radius of the base metal [Å]) Contains at least one or more additive metals having an atomic size factor of 13% or more,
A method for producing an alloy powder, characterized in that the alloy having an intermediate phase is pulverized using a mechanical pulverizer. 2 The following general formula between two _or more types of additive metals [ _] [(γ _X ~ γ _X1 )/γ The method according to claim 1, wherein the atomic size factor expressed as atomic radius of the element [Å] γ _X1 ; atomic radius of the element added in a smaller amount than γ _X [Å]) is 13% or more.