RU2424382C1 - Electrolyte-suspension on base of iron for production of wear resistant coating on parts of machines including nano powder on base of tungsten carbide - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: electrolyte-suspension contains nano-powder on base of tungsten carbide containing particles of spherical shape of dimension 0.1 mcm and less.

EFFECT: increased stability for process of application coating, raised wear resistance and upgraded physical-mechanical properties.

1 ex, 1 tbl

Description

The present invention relates to the field of powder electroplating, and in particular to materials for the production of composite galvanic coatings, can be used to create wear-resistant coatings in conditions of a single, serial and mass production.

Known ironing electrolyte to obtain coatings on machine parts, consisting of ferric chloride, water and hydrochloric acid [1, p.23].

The disadvantage of electrolyte for producing coatings on machine parts is that the wear resistance of the coatings is relatively low.

The closest technical solution, selected as a prototype, is an electrolyte suspension based on iron to obtain wear-resistant coatings on machine parts, including tungsten carbide powder with particle sizes of 1-10 microns.

The disadvantage of using the known electrolyte suspension is the need for constant directional movement of the particles of the dispersed phase to the cathode, as well as the low wear resistance and physical and mechanical properties of the obtained coatings [2, p. 45, 193].

The task of the invention is to increase the stability of the coating process, wear resistance and physico-mechanical properties of the coatings.

The problem is solved in that as a dispersed phase, nanopowders based on tungsten carbide with a particle size of 0.1 μm or less are used.

These nanopowders are obtained from wastes of a VK8 grade alloy containing 8% cobalt and 92% tungsten carbide by electroerosive dispersion. It was experimentally established that the chemical composition of the nanopowder obtained from the indicated grade of hard alloy slightly differs from the initial one.

A technological installation for obtaining nanopowders from solid alloy waste consists of a spark source power supply, a reactor, and a control system. In the reactor between the electrodes are granules - pieces of an alloy of arbitrary shape and size. The electrodes are made of dispersible material. The interelectrode gap is filled with distilled water so that the granule layer is immersed in this liquid.

In contact, the granules form many electrical contacts connected in series in parallel between the electrode gap. One discharge pulse between the electrodes in the layer of granules immersed in the working fluid sparks in many places. At the points of contact, the material of the granules can be not only melted, but also brought to higher temperatures at which evaporation and explosive removal of the material is possible. In this case, the particles of the substance come off the surface of the granules and are instantly cooled by a liquid. As a result of electrical erosion, particles of a predominantly spherical shape arise.

Example

Electrolyte suspension technology

1. Simple ferrous chloride electrolyte (FeCl ₂ · 4H ₂ O - 300 g / l, НСl - 0.8-1.5 g / l) is prepared according to the standard method [1, p.23].

2. The electrolyte suspension with the addition of nanopowders based on tungsten carbide is obtained as follows:

To obtain maximum wear resistance, nanopowders based on tungsten carbide at a concentration of 100 g / l are introduced into small amounts in the prepared ironization electrolyte and mixed thoroughly. Due to the fact that the particle size of the powder in the suspension is up to 1 μm, preliminary mixing of the suspension before deposition of the coating is sufficient and there is no need for a constant directional movement of particles to the cathode.

Ironing modes: cathodic current density - 40-60 A / dm ² , electrolyte temperature - 60-80 ° С. The anode material is Steel 10 GOST 1050-88, the cathode is the finger of the piston engine SMD-14/18/20 (surface area - 1.3 dm ² ), the coating time is 40-60 minutes (up to a layer thickness of 0.5 mm to the side).

The electrolyte suspension with particles up to 1.0 μm in size is kinetically stable and, for technological reasons, is most suitable for producing composite galvanic coatings. In the process of electrodeposition, the electrolyte does not need mixing. Under the action of powder particles based on tungsten carbide up to 0.1 μm in size, the crystal lattice is distorted. Coatings with pronounced defects in the crystal lattice have the greatest hardness. An electrolyte suspension based on tungsten carbide with a particle size of up to 0.1 μm helps to increase the microhardness and wear resistance of coatings of machine parts.

The use of tungsten carbide nanopowders with a particle size of 0.1 μm or less instead of tungsten carbide powder with a particle size of 1-10 microns as a dispersed phase can increase the stability of the process (there is no need to mix the electrolyte during the entire coating time), relative wear resistance ( GOST 23.208-79 Ensuring wear resistance of products — Method for testing materials for wear resistance by friction against non-rigidly fixed abrasive particles) of machine parts coatings by an average of 20%, and together in order to increase their resource. Increasing the resource of machine parts will reduce the cost of their restoration and repair.

The concentration of nanopowder based on tungsten carbide in the electrolyte, g / l Relative wear resistance 0 one fifty 1,11 one hundred 1.27 150 1.28

Information sources

1. Melkov M.P. Electrolytic build-up of machine parts with solid iron. Saratov: Volga Book Publishing House, 1964. - 204 p.

2. Borodin I.N. Powder electroplating. - M.: Mechanical Engineering, 1990. - 240 p.

Claims (1)

An electrolyte suspension based on iron to obtain wear-resistant coatings on machine parts, including nanopowder, characterized in that the electrolyte suspension contains a nanopowder based on tungsten carbide containing spherical particles with a size of 0.1 μm or less.