SU802395A1 - Method of aluminizing preferably nonmetallic articles - Google Patents

Description

The invention relates to chemical-thermal treatment of materials in a molten metal and can be used to improve the phyico-mechanical properties of non-metallic materials.

Known chemical-thermal treatment of low-carbon steels and alloys based on iron in molten aluminum at temperatures from 700 to 800 ° C [1].

Using the known method of chemical thermal treatment for the treatment of low-carbon and heat-resistant steels can increase the strength of the machined parts on

4-8 kg / mm ¹ and increase their corrosion resistance.

A disadvantage of the known method of chemothermal treatment is the inability to process non-metallic tool materials at given temperatures, since molten aluminum at these temperatures has poor adhesion properties to non-metallic tool materials: diamond, cubic boron nitride and composites based on them.

The aim of the invention is to increase the strength of non-metallic tool materials.

The goal is achieved in that the thermochemical treatment of aluminum melt ⁵ is carried out at a melt temperature of 1050-1300 ° C, and subjected to treatment nemetal • tallic tool materials: ^diamond: cubic boron nitride, and composites thereof.

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An increase in the temperature of aluminum melt from 700-800 ° C to 1050-1300 ° C reduces the contact angle of aluminum wetting non-metallic tool materials and> ₁₅ contributes to the penetration of molten aluminum into the pores and microcracks of the material and, as a result of chemical interaction of aluminum, for example, boron nitride , the formation of aluminum borides and nitrides occurs, which fill the pores and microcracks, that is, they heal. This leads to a significant increase in the strength of polycrystals of non-metallic superhard materials.

the melt is 10 min. Compressive Strength blocks after the heat treatment of aluminum in the melt is 210 to T / ² mm against 120 kg / mm ² before the heat treatment.

Example 2. Blocks of cubic boron nitride are immersed in an aluminum melt and kept in the melt at a temperature of 1100 ° C for 15 minutes. The compressive strength of the blocks after heat treatment is 10 300-320 kg / mm ² .

Example 3. Blocks of polycrystals of diamond, is subjected to heat treatment in a molten aluminum at a temperature of And 00 ° C for 5 minutes The compressive strength of the blocks is 250 kg / mm ² compared to 155 kg / mm ² before heat treatment.

Example 4. Blocks of polycrystalline cubic boron nitride are subjected to heat treatment in a molten aluminum at 2Q temperature of 1300 ° C for 15 minutes The compressive strength of the blocks after heat treatment is 315 kg / mm ² compared with 125 kg / mm ² before heat treatment.

The proposed method of chemical-thermal treatment 25 allows to process polycrystalline non-metallic tool materials and increase their strength by 2-2.5 times.

Claims (4)

(54) METHOD OF PRODUCT ALITIUM, MOSTLY FROM NON-METALLIC MATERIALS The essence of the invention is as follows. Polycrystalline blocks of non-metallic tool materials, for example, cubic nitrideboron, diamond, and composites based on them, are immersed in the aluminum melt with a temperature of 1050–1300 ° C. The blocks are kept at this temperature for 5-60 minutes, as a result of which aluminum, penetrating into the pores and microcracks of the blocks, interacts with the material of the block. or aluminum carbide (when processing diamond polycrystals). The resulting compounds fill and heal pores and microcracks in the polycrystals of non-metallic tool materials, which leads to an increase in their strength by 2-2.5 times. The treatment at temperatures below 1000 ° C does not give such a significant effect on the increase in strength, since even at 1050 ° C aluminum badly wets cubic boron nitride and the mixing angle is 140 °. At such wetting angles, capillary forces prevent the penetration of aluminum into the pores and microcracks and they are not healed. Increasing the temperature of the melt to 1100 ° C already reduces the wetting angle of cubic boron nitride by aluminum to 90-70 °. At such a wetting angle, under the action of capillary forces, aluminum penetrates into the pores and fissures, they heal and the strength of polycrystals is increased. Increasing the treatment temperature above 1300 ° C is impractical due to technological difficulties. Example 1. I put a crucible with aluminum in an electric furnace and heat it to 1050 ° C. Then I immerse polycrystalline blocks of cubic boron nitride in an aluminum melt. The holding time of the blocks in the melt is 10 minutes. The compressive strength of the blocks after heat treatment in the molten aluminum is 210 kg / mm against 120 kg / mm before heat treatment. Example 2. Blocks of cubic boron nitride are immersed in an aluminum melt and kept in the melt at a temperature of 1100 ° C for 15 minutes. Compressive strength of blocks after heat treatment is 300-320 kg / mm. Example 3. Blocks of polycrystals of diamond, subjected to heat treatment in the molten aluminum at a temperature of 1100 ° C for 5 minutes. The compressive strength of the blocks is 250 kg / mm compared with 155 kg / mm prior to heat treatment. Example 4. The blocks of polycrystalline cubic boron nitride are heat treated in an aluminum melt at a temperature of 1300 ° C for 15 minutes. The compressive strength of the blocks after heat treatment is 315 kg / mm compared with 125 kg / mm before heat treatment. The proposed method of chemical heat treatment permits the processing of polycrystalline nonmetallic tool materials and an increase in their strength by 2–2.5 times. The invention of the method of aluminizing products, mainly from non-metallic materials, by treatment in the molten aluminum, characterized in that, in order to increase the strength of the products, the treatment is carried out in the melt at 1050-1300 ° C. Sources of information taken into account in the examination 1. Minkevich A. N. Chemical-thermal processing of metals. M., 1965, p. 15 & -162 (prototype).