RU2013187C1 - Method of manufacture of multilayer materials - Google Patents

Abstract

FIELD: manufacture of antifriction articles. SUBSTANCE: method involves application of intermediate layer onto compact base by means of filling metal powder whose particle medium size is in the range of 50-400 microns, scorching and pressing powder layer. As material of intermediate layer such a material or alloy is selected which possesses diffusion coherence with basic material and powder layer. EFFECT: high quality of multilayer material. 2 tbl

Description

 The invention relates to powder metallurgy, in particular to methods for manufacturing composite materials. The method can find application in mechanical engineering, automotive, tractor manufacturing and other industries in the manufacture of antifriction, friction and other products from multilayer materials.

 Known methods for the manufacture of bimetallic materials, including the preparation of the mixture, applying the mixture to a steel base, sintering and impregnation [1].

 There are also known methods of manufacturing composite materials by preparing a steel base, preparing a charge, applying a mixture to a steel base, impregnating and sintering [2].

 There are also known methods of manufacturing multilayer materials by forming a working layer, sintering and welding with a steel base using thin bronze foil [3].

 Methods of manufacturing multilayer materials are laborious, require the use of special technological equipment, have low productivity and a long manufacturing time, and also do not provide stability of strength properties at the contact points of the components.

 The closest in technical essence and the achieved effect is a method that includes forming a powder part, applying an intermediate layer in the form of a slip on the compact metal part, assembling by applying the powder part to the compact part through the slip and co-sintering (A.S. USSR No. 1540944, cl. B 22 F 7/04, 1990).

 The disadvantage of this method is the relatively low stability of the adhesion force of the components of the multilayer materials.

 The aim of the invention is to increase the stability of the adhesion forces of the powder and compact parts of the multilayer materials.

 The goal is achieved by the fact that in the known method, including molding a powder part, applying an intermediate layer to a compact metal part, assembling and co-sintering, a metal powder with an average particle size of 50-400 microns diffusely bonded to compact and powder materials is used as an intermediate layer parts, which, after application by the free-filling method, are baked to the compact part, and assembly is carried out at the stage of molding the powder part.

 Comparison of the claimed technical solution with the prototype made it possible to establish compliance with its criterion of "Novelty." When studying other technological solutions in this technical field, the features that distinguish the claimed invention from the prototype were not identified and therefore they provide the claimed technical solution with the criterion of "Significant differences".

 The method is as follows.

 A metal powder, which serves as an intermediate layer, is applied to the compact metal part by free-flowing. The average particle size of the powder should be 50-400 microns. The thickness of the applied layer, depending on the need, can range from 1 to 4 average particle sizes of the powder. As the material of the powder, it is necessary to select the material that diffusely binds both to the compact material and to the material of the powder parts. Moreover, the melting temperature of the material of the intermediate layer should be higher than the sintering temperature of the material of the powder part. Then, the deposited metal powder is baked to a compact metal part in a protective atmosphere at temperatures ensuring a strong connection of the powder particles to the compact part, but without melting, since in this case there will be no required surface relief to obtain a strong connection of the components of the multilayer material. After the powder is baked, the powder part is pressed onto the compact metal part from the side of the intermediate layer. The resulting preform is sintered in a protective atmosphere. If necessary, after sintering, repeated pressing or cold stamping, or hot stamping, or other additional operations are performed, however, these operations do not affect the stability of the adhesion forces of the layers, but serve to obtain higher physicomechanical properties.

 It was experimentally established that the greatest stability of the adhesion strength of the layers is ensured by using an intermediate layer of metal powder with an average particle size in the range of 50-400 microns. With a decrease or increase in the average particle size of the intermediate layer, the stability of the adhesion strength of the layers decreases and, in addition, the bond strength of the layers decreases. This is because very fine powder (less than 50 microns) does not provide sufficiently strong adhesion of the powder part to the intermediate layer due to the relatively smooth surface relief, and very large (more than 400 microns) do not allow to obtain a sufficient amount of free surface energy, which also reduces the strength of the connection.

 According to the described method, friction material for dry friction (examples 1-5), antifriction material (examples 6-10) and material for the bases of transistors (examples 11-15) were made. The resulting materials were tested for separation of the layers. The test results are given in table. 1.

PRI me R s 1-5. An iron powder containing 10% copper powder was deposited on a metal sheet of steel 65G. The average particle size was 20, 50, 250, 400 and 600 microns. Then, sintering was conducted to steel powder in an atmosphere of dissociated ammonia at 1150 ^{° C} for 2 hours, pressed onto the friction material (composition: 48% iron powder, 20% copper, 6.5% manganese powder, and 4% of molybdenum disulphide, 6.5% boron nitride, 10% boron carbide and silicon carbide, 3.5%) at a pressure of 100 MPa and sintered at 1020 ^{° C} in dissociated ammonia atmosphere.

PRI me R s 6-10. A bronze powder was applied to a steel billet 45 (composition: 90% copper and 10% tin). The average particle size corresponded to the values of examples 1-5. Sintering was performed in an atmosphere of dissociated ammonia at 830 ° ^C overmolding antifriction layer (composition: 87% of copper powder, 9% tin and 4% graphite) was carried out at a pressure of 150 MPa, and sintering - at 820 ^{° C} in an atmosphere of endogas.

PRI me R s 11-15. Copper powder was applied to a nickel-coated molybdenum sheet. The average particle size corresponded to the values of examples 1-5. Then, sintering was carried out to a molybdenum powder preform at 1000 ^{° C} in an atmosphere of endogas, overmolding copper powder brand MPS-1 at a pressure of 150 MPa and sintered at 1000 ^C in an atmosphere of endogas.

 Similar to examples 1-15, the products were made according to the prototype method. The test results are given in table. 1.

где n - количество опытов;
х_i - текущее значение величины силы сцепления;

- среднее значение величины силы сцепления.The stability of the adhesion strength of the layers was determined by the magnitude of the variance of the values obtained from the tests
D =

where n is the number of experiments;
x _i is the current value of the adhesion force;

- the average value of the adhesion force.

 As can be seen from examples 1-15 (table. 1), the smallest dispersion values were obtained using powders with an average particle size of 50 to 400 microns and are 3.6-4.4 for the material of examples 2-4; 3.6-5.2 - for the material of examples 7-9; 2.9-3.3 - for the material of examples 12-14. The dispersion of the magnitude of the adhesion force for multilayer materials manufactured by the prototype method, respectively, is 6.9; 8.1 and 6.0.

 To identify the effectiveness of the proposed method, the dispersions (D) were compared according to the Fisher criterion. The obtained values of the dispersion ratios (Table 2) suggest that the proposed method improves the stability of the adhesion force of the materials being joined, and for this experimental sample this difference is statistically significant with a probability of more than 75%.

 Thus, the application of the proposed method for the manufacture of multilayer materials in comparison with the prototype can reduce the dispersion of 1.6-2.2 times, that is, significantly increase the stability of the magnitude of the adhesion force of the powder and compact parts.

Claims (1)

 METHOD FOR PRODUCING MULTILAYERED MATERIALS, including applying an intermediate layer to a compact metal base, applying a powder layer to an intermediate layer and co-sintering, characterized in that the intermediate layer is applied by freely filling a metal powder with an average particle size of 50 - 400 microns and subsequent baking, and As the material of the intermediate layer, a metal or alloy having diffusion bonding with the base material and the powder layer is selected, and the powder layer is pressed d.

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