RU2617069C1 - Method of increasing heat resistance of copper parts - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: method of producing heat-resistant cuprum-yttrium coating on the surface of copper parts, comprising heating of the working molten salt to the temperature of 500-700°C in the container of beryllium or alundum oxide positioned in a sealed vessel, in inert-gas atmosphere, at the same time the copper part and a plate from metal yttrium are positioned in the molten mass in the current of inert gas, fixed at molybdenum or tungsten suspensions without contact between each other and the walls of the container, holding of the part in the molten salt for 1-4 hours with current-free diffusion alloying of copper surface with yttrium to form intermetallic compounds, extraction of the part from the mentioned molten mass and subsequent homogenizing annealing at temperature of 400-500°C for 1 hour in an inert atmosphere, cooling of the part in an inert atmosphere to room temperature and flushing of the salt remains from the part surface, wherein the working molten salt comprises, wt %: eutectic mixtures of alkali-metal chlorides 95.0-99.0, yttrium trichloride 5.0-1.0. Production of the heat-resistant coating on the surface of the copper part is ensured.

EFFECT: increased heat resistance of the parts made of copper and copper alloys.

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Description

The present invention relates to the field of corrosion protection of non-ferrous metals, namely to the deposition of metal coatings by chemical-thermal treatment, and can be used to increase the heat resistance of parts made of copper and copper alloys, for example, nozzles of torches for argon-arc welding, holders of arc melting furnaces , tuyeres of blast furnace and converter furnace melting units.

From the existing level of technology there is known a method of manufacturing heat-resistant and heat-resistant dispersion-strengthened products based on copper (RF Patent RU 2117063 C1, IPC C22C 1/04, C22C 1/10, Z. No. 97106864/02 of 04.24.1997, publ. 10.08. 1998). The disadvantage of this technical solution is the need to use copper in powder form, followed by molding the part by powder metallurgy, which affects the strength characteristics of the parts.

Also known is a method of increasing the heat resistance of copper by treating liquid copper with nanosecond electromagnetic pulses (NEMI) (RF Patent RU 2355511 C2, IPC B22D 27/20, C22F 3/02, Z. No. 2007124218/02 of 06.27.2007, publ. 05.20.2009 g.). The disadvantage of this method is the need to bring copper to a liquid state by heating to high temperatures (about 1300 ° C), which leads to high energy costs for heating, as well as the use of sophisticated technological equipment - a NEMI generator.

Another technical solution is the method of applying combined coatings to electrical copper parts by galvanic deposition of yttrium in a salt melt (SU 1565060 A1, MPK S23C 10/24, part No. 4382111/02 of 05/05/1988, published on 06/27/1988, ) The disadvantage of this method is the need to use expensive palladium chloride.

Closest to the claimed technical solution is a method of applying metal coatings (RF Patent RU 2058422 C1, IPC S23C 10/24, s.No. 93046241/02 of 09/30/1993, publ. 04/20/1996). The disadvantage of this technical solution is the high operating temperatures of 850-1000 ° C, which leads to an increase in energy costs for maintaining such temperatures.

The technical result obtained due to the use of the claimed method is to obtain a coating having high heat resistance. Heat resistance is enhanced by the presence of a heat-resistant copper-yttrium intermetallic compound on the surface of the part.

A method of increasing the heat resistance of copper parts by producing a copper-yttrium coating on a copper surface is as follows:

1. Heat the working salt melt to a temperature of 500-700 ° C in a container of beryllium oxide or alunda, while the container with the melt must be in an atmosphere of inert gas, such as argon, in a hermetically sealed container;

2. At the same time, in a stream of inert gas, a copper part and a plate of metallic yttrium are placed in a working salt melt, mounted on molybdenum or tungsten suspensions so as to exclude their contact between themselves and the walls of the container;

3. The copper part and the yttrium metal plate are kept in the working salt melt for 1-4 hours, while the currentless diffusion saturation of the copper surface with yttrium occurs with the formation of intermetallic compounds;

4. The copper part is lifted above the melt, homogenization annealing is carried out at a temperature of 400-500 ° C for 1 hour in an inert atmosphere;

5. Cool the copper part in an inert atmosphere to room temperature, wash off the remaining salt from the surface of the part.

The technical result - the formation of a coating - is achieved in salt melts containing, mass. %: eutectic mixtures of alkali metal chlorides 95.0-99.0, yttrium trichloride 5.0-1.0. Diffusion coatings are non-porous, well adhered to the substrate material.

The advantage of the proposed method is that the operating temperature is lower than in the known method (RU 2058422 C1 of 04/20/1996), which reduces the energy cost of the saturation process.

Examples of the claimed invention

Example 1. In a crucible of beryllium oxide melt 95 wt. % eutectic mixture of lithium and potassium chlorides, 5 wt. % yttrium trichloride. At a temperature of 500 ° C, a copper part and a yttrium plate are placed in the melt. Within 1 hour receive a coating of copper-yttrium with a thickness of 50 μm.

Example 2. In the alundum crucible, a melt of 96 masses is prepared. % eutectic mixture of sodium chloride and cesium with the addition of 4 mass. % yttrium trichloride, at a temperature of 600 ° C for 2 hours, a copper-yttrium coating 150 μm thick is obtained on the surface of the copper part.

Example 3. In the melt of 95 mass. % equimolar mixture of sodium and potassium chlorides and 5 wt. % yttrium trichloride saturate the copper part with yttrium at a temperature of 700 ° C for 3 hours. A copper-yttrium coating of 180 μm thickness is obtained.

Claims (2)

A method of obtaining a heat-resistant coating of copper-yttrium on the surface of copper parts, comprising heating the working salt melt to a temperature of 500-700 ° C in a container of beryllium oxide or alunda, which is in a hermetically sealed container, in an inert gas atmosphere, simultaneously in the melt in an inert gas stream place a copper part and a plate made of yttrium metal, mounted on molybdenum or tungsten suspensions without contact between themselves and the walls of the container, holding the part in salt melt for 1-4 hours with a currentless diffus ion saturation of the surface of copper with yttrium with the formation of intermetallic compounds, removing the part from the aforementioned melt and conducting subsequent homogenization annealing at a temperature of 400-500 ° C for 1 h in an inert atmosphere, cooling the part in an inert atmosphere to room temperature and washing off salt residues from the surface of the part , while the working salt melt contains, wt.%: eutectic mixtures of alkali metal chlorides 95.0-99.0 yttrium trichloride 5.0-1.0