JPH0499101A - Cu-ni series alloy powder and manufacture thereof - Google Patents

Abstract

PURPOSE:To give excellent wear resistance and corrosion resistance to Cu-Ni-Al alloy powder by oxidizing the Cu-Ni-Al alloy powder at high temp. and successively, reducing it at low temp. CONSTITUTION:The Cu-Ni-Al alloy raw material powder composed of wt.% of 1.5-10% Al, 1-45% Ni and the balance Cu with inevitable impurities is heated and held at 700-1100 deg.C in an oxidizing atmosphere and oxidized desirably in powder fluidizing condition. By this treatment, oxide powder having structure, in which cyclic complex oxide phase aggregated with fine (Cu, Ni, Al) O as ring-state exists between the powder center part and the powder peripheral part in all cross section passing the powder center part in matrix composed of (Cu, Ni) O as essential body, is formed. The above oxide powder is heated and held at 200-450 deg.C in a reducing atmosphere to execute the reducing treatment and the matrix in the oxide powder is substantially made to Cu-Ni or Cu-Ni-Al alloy and also the cyclic complex oxide phase is made to ring hardened phase containing fine Al2O3 as essential body.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a Cu-Ni alloy powder particularly suitable for use in producing a sintered body having excellent wear resistance and corrosion resistance, and a method for producing the same. It is related to.

[Conventional technology]

Conventionally, as described in, for example, JP-A-83-241128 and JP-A-59-150043, AfI: 0.1 to 1% is contained in weight% (hereinafter % indicates weight%). After surface oxidation treatment is performed on the Cu-Al alloy raw material powder, the remainder of which has a composition essentially consisting of All, under the conditions of heating and holding at a temperature of 300 to 500°C in the atmosphere, and then in an inert gas atmosphere. , heating and holding at a temperature of 800 to 900°C, internal oxidation treatment under the following conditions, followed by heating and holding at a temperature of 400 to 800°C in a reducing atmosphere for the purpose of removing excess oxygen, under the conditions of There is a known method for producing a Cu alloy powder having a structure in which fine aluminum oxide (hereinafter referred to as Af1203) generated by the internal oxidation is uniformly dispersed in a Cu or Cu-Al) alloy matrix by performing a reduction treatment. ing.

In addition, the Cu alloy powder produced by this method is used as a raw material powder when manufacturing structural members of various drive devices such as oil-impregnated bearings, guide bushes, and valve seats by ordinary powder metallurgy. It is also well known.

[Problem to be solved by the invention]

On the other hand, in recent years, the performance and speed of various drive devices have increased dramatically, and as a result, the environments in which these structural members are used have become even more severe, and as a result, structural members have become more wear-resistant and corrosion-resistant. However, structural members made of sintered bodies manufactured using Cu alloy powder manufactured by the conventional internal oxidation method do not have sufficient wear resistance.
Moreover, it does not exhibit sufficient corrosion resistance in a severe corrosive environment, and therefore it is currently impossible to meet these demands satisfactorily.

In addition, in the conventional Cu alloy powder produced by the above-mentioned internal oxidation, A I 20 g uniformly dispersed in the substrate.
Attempts have been made to improve wear resistance by increasing the content of A Il 2 O a, but when increasing the content of A Il 2 O
In proportion to this, the ratio of All203 grains exposed on the powder surface increases, and as a result, the A120a grains become coarser and poor quality, and the sinterability is significantly reduced. The strength of the compact is reduced, and it cannot be put to practical use in terms of strength.

[Means to solve the problem]

Therefore, from the above-mentioned viewpoint, the present inventors developed a raw material powder using this material in order to produce a sintered body that exhibits excellent wear resistance and corrosion resistance when used as a structural member of various drive devices. As a result of research focusing on a certain Cu alloy powder, it was found that 0.1 to 1
% Al content, relatively large proportion of 1.5~l
Using a Cu'Ni-Al1 alloy powder containing 0% Ap and 1 to 45% Ni-, this Cu-Ni--Al alloy raw material powder was subjected to the above-mentioned conventional internal oxidation manufacturing method. When oxidation treatment is performed at a temperature of 700 to 1100°C, which is relatively higher than the oxidation temperature of 300 to 500°C, preferably in a powder fluidized state, a composite oxide mainly composed of Cu and Ni- (hereinafter referred to as (Cu .

A fine composite oxide of Cu, Ni-, and Al (hereinafter referred to as (C
u. Ni. A cyclic composite oxide phase formed by the agglomeration of (denoted as /l)O) in a ring shape, in other words, a fine (Cu.Ni.All)O that forms a layer inside the powder and is aggregated and distributed in a shell shape.
An oxide powder having a structure in which a cyclic composite oxide phase composed of
200°C, which is relatively low compared to the reduction temperature of 0 to 800°C.
When reduction treatment is performed at a temperature of ~450°C, the main (Cu, Ni)O that formed the base of the oxide powder becomes Cu-
reduced to Ni and the above (Cu, Ni, AfI)O
The cyclic composite oxide phase composed of Since the Al1203 content is relatively high, the sinterability is not impaired because the Al1203 content is relatively high. It is possible to produce a sintered body with high strength, and this sintered body has excellent corrosion resistance due to the Ni content, and also exhibits excellent wear resistance due to the high content of A I 20 a. The research results were obtained.

This invention was made based on the above research results, and includes: A, Q: 1.5-10%, Ni: 1-45%,
A Cu-Ni--Al1 alloy raw material powder having a composition of By performing oxidation treatment under certain conditions, fine (Cu, N
i, Al7) Form an oxide powder with a structure in which a cyclic composite oxide phase formed by agglomerating O into a ring, and then apply the oxide powder to the oxide powder at 200 to 450°C in a reducing atmosphere. Heated and held at a temperature of , and subjected to reduction treatment under the conditions of , to substantially convert the base of the oxide powder into a Cu-Ni or Cu-Ni--Al alloy, and transform the cyclic composite oxide phase into a fine Al12
A method for producing a Cu-Ni alloy powder through the main steps, which has an annular hard phase mainly composed of 03, and the powder produced by this method: 1): 1.5 to 9.2%, oxygen = 1. 3-8.2
%, Ni: 0.9 to 41.3%, the bottle has a composition consisting of Cu and unavoidable impurities, and the powder center is formed on a base material consisting essentially of Cu-Ni or Cu-Ni-Ag alloy. A Cu-Ni-based alloy powder having a structure in which a ring-shaped hard phase mainly consisting of fine Al2o3 agglomerated in a ring shape exists between the powder center and the powder periphery in every cross section passing through the powder. It is something that you have.

Next, in the Cu-Ni alloy powder of the present invention and its manufacturing method, the reason why the component composition and manufacturing conditions are limited as described above will be explained.

A, Composition of Cu-Ni alloy powder (a) Al2 and oxygen A, Q combine with oxygen to form fine A If' 203 that forms a layer inside the powder and is aggregated and distributed in a shell shape. It has the effect of significantly improving the wear resistance of sintered bodies manufactured using it as a raw material powder without impairing its sinterability.In this case, once the AΩ content is determined, oxygen must be removed by oxidation treatment. The content is also determined, so if the All content is less than 1.5%, the oxygen content will also be 1.5%.
If the AI content exceeds 9.2%, the formation ratio of A 1120a is insufficient and the desired excellent wear resistance cannot be ensured.On the other hand, if the AI content exceeds 9.2%, the oxygen content also becomes 8.2%.
If the AfI content exceeds 2%, and as a result, a large amount of Ag2O3 is formed, coarsening of the A 1' 20 a grains is unavoidable and aggressiveness appears. was determined to be 1.5 to 9.2%, and the oxygen content was determined to be 1.3 to 8.2%.

(b) Ni The N+ component has the effect of improving corrosion resistance, but if its content is less than 0.9%, the desired effect of improving corrosion resistance cannot be obtained; on the other hand, if its content exceeds 41.3%, When a sintered body is manufactured using this material, the toughness of the material decreases, so the content is reduced to 9 to 41.3%.
It was determined that

B. Manufacturing conditions (a) Component composition of the Cu-Ni--Ajl1 alloy raw material powder When the All content is less than 1.5%, the annular shape inside the (Cu, Ni, Aρ)0 powder formed by the oxidation treatment Agglomeration is not sufficiently carried out, and as a result, a relatively large amount of A i) 20 s is present on the powder surface after reduction treatment, which reduces sinterability and causes a decrease in the strength of the sintered body. When the AfI content exceeds 10%, the particle size of (Cu, Ni.AII) 0 formed by oxidation treatment and Ag2O3 formed by reduction treatment becomes coarse, and when this is made into a sintered body, it is difficult to attack opponents. A.
The N content was determined to be 1.5-10%.

Furthermore, if the Ni content is less than 1%, the produced Cu-N
If the Ni content in the i-series alloy powder becomes less than 0.9%, it becomes impossible to produce a sintered body with the desired corrosion resistance.On the other hand, if the Ni content exceeds 45%, The Ni content of the powder was set at 1 to 45% because the Ni content of the powder would be higher than 41.3% and the toughness of the sintered body produced using it would decrease. .

(b) Oxidation treatment temperature If the temperature is less than 700°C, (Cu, Ni.
) Cyclic aggregation of O is insufficient, while its temperature is 110
If the temperature exceeds 0℃, the powders tend to fuse together even if they are fluidized, so the temperature should be adjusted to 700 to 1100℃.
It was determined that

(c) Reduction temperature If the temperature is less than 200°C, it will take a long time to reduce the oxide powder, making it impractical. On the other hand, if the temperature exceeds 450°C, Al1203 formed in the reduction process will become a negative flame. As a result, the aggressiveness of the sintered body toward others increases, so the temperature was set at 200 to 450°C.

〔Example〕

Next, the Cu-Ni alloy powder of the present invention and its manufacturing method will be specifically explained with reference to Examples.

Cu-Ni--Al alloy raw material powders having the average particle diameters and Ni and Al contents shown in Table 1 were prepared, and these Cu-, Ni-Aff alloy raw material powders were added with the powders also shown in Table 1. Methods 1 to 8 of the present invention and conventional methods 1 to 3 were carried out by performing oxidation treatment, internal oxidation treatment if necessary, and reduction treatment under the conditions described above to obtain Cu-Ni alloy powders 1 to 8 of the present invention, respectively. and conventional Cu
Alloy powders 1 to 3 were manufactured.

Next, the component compositions of the various powders obtained as a result were measured, and the cross-sectional structure was observed using a metallurgical microscope (magnification: 1000 times).
For Ni-based alloy powders 1 to 8, the particle size on an arbitrary straight line passing through the center of the cross section of each of the 30 powders, as well as the outer diameter and inner diameter of the annular hard phase were determined to be 1111, and the average value of these was calculated. did.

These results are shown in Table 2.

Furthermore, using these various powders as raw material powders, this was press-molded into a green compact at a pressure of 5 tons/cj, and the green compact was heated to a predetermined temperature within the range of 900-1100°C in hydrogen for 30 minutes. Sintered under holding conditions, cross section: 101
A sintered body with dimensions of 0 mm x 1 O, length: 55 m + i was manufactured, and the tensile strength of this sintered body was measured for the purpose of evaluating the strength. A wear test was conducted in a gasoline combustion gas atmosphere.

In addition, the wear test was performed using an outer diameter of 40+a with the rotation axis horizontal.
mx inner diameter: 30u+x length: 15mm cast iron (Fe12
) heat treated ring (hardness: HRC50) from above,
A test piece cut out from the above sintered body with dimensions of 8 mm x 8 m x 351 h was brought into contact with the test piece horizontally, and in this state a load of 5 kg was applied vertically to the test piece, unleaded gasoline was combusted, and then cooled to 600°C. 10ff/si
The test was carried out by rotating the ring at a circumferential speed of 1.2 m/sec while spraying onto the test piece at a rate of n, and determining the maximum wear depth of the test piece after 10 minutes. These results are also shown in Table 2.

〔Effect of the invention〕

As shown in Table 1.2, according to methods 1 to 8 of the present invention,
It is possible to produce a Cu-Ni alloy powder (Cu-Ni alloy powders 1 to 8 of the present invention) in which a ring-shaped hard phase formed by agglomerating fine Al2O3 in a ring shape in a cross-sectional structure is present inside the powder. Although the Cu-Ni alloy powders 1 to 8 of the present invention have a high Al content as described above, the Aj720
3 is sealed inside the powder, so
When a sintered body is manufactured using this as a raw material powder, good sinterability is ensured, so not only can a high-strength sintered body be manufactured, but also a relatively high-content sintered body can be manufactured. Due to the inclusion of Al2O3 and Ni, the sintered body manufactured from this material has excellent wear resistance in a corrosive environment, with very little wear on the heat-treated ring, which is the mating material, and in other words, in a state where aggressiveness to the mating material is significantly suppressed. In contrast, the Cu alloy powder produced by conventional methods 1 to 3 (conventional Cu
Alloy powders 1 to 3) have a structure in which Al2O3 is uniformly distributed throughout the powder, so combined with the relatively low Al content, there is not much deterioration in sinterability, but N
It is clear that the produced sintered body exhibits relatively low strength due to the lack of reinforcement of the base material by i, and also shows considerably poor results in terms of wear resistance in a corrosive environment. .

As described above, according to the method of the present invention, it is possible to produce a Cu-Ni alloy powder in which a relatively large amount of fine AlI2O3 forms a layer inside the powder and is sealed in a shell shape. The produced Cu-Ni alloy powder has extremely good sinterability, and the sintered body produced using it has high strength and, combined with the Cu-Ni content, has excellent wear resistance in corrosive environments. In addition to the above, when this material is used to manufacture structural members for various drive devices such as block rings, rocker arm tips, brake butts, and clutch plates, it exhibits excellent performance. This brings about industrially useful effects such as the ability to

Claims (3)

[Claims] (1) Al: 1.5-9.2%, oxygen: 1.3-8.2
%, Ni: 0.9 to 41.3%, with the remainder consisting of Cu and unavoidable impurities (weight %), and a base material consisting essentially of Cu-Ni or Cu-Ni-Al alloy. , a structure in which a ring-shaped hard phase mainly composed of fine aluminum oxide agglomerated in an annular shape exists between the powder center and the powder periphery in every cross section passing through the powder center. -Ni alloy powder. (2) Cu-Ni-Al alloy raw powder having a composition (weight %) containing 1.5 to 10% Al, 1 to 45% Ni, and the rest consisting of Cu and unavoidable impurities, oxidation Oxidation treatment is carried out under the conditions of heating and holding at a temperature of 700 to 1100°C in a neutral atmosphere, and the powder center is oxidized to the base material mainly consisting of a composite oxide of Cu and Ni in all cross sections passing through the powder center. Fine Cu between the powder periphery
A composite oxide of Ni and Al is aggregated into a ring to form an oxide powder having a structure in which a cyclic composite oxide phase exists, and then the oxide powder is heated to a temperature of 200 to 450 in a reducing atmosphere. By heating and holding at a temperature of ℃, reduction treatment is performed under the conditions of Cu- characterized by having an annular hard phase mainly composed of aluminum.
A method for producing Ni-based alloy powder. (3) The method for producing a Cu-Ni alloy powder according to claim (2), wherein the oxidation treatment is performed while fluidizing the Cu-Ni-Al alloy raw material powder. .