RU2506344C1 - Titanium nitride coating manufacturing method - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention refers to methods of wear-resistant coatings application, namely to coatings from titanium nitride, and may be used for metal working. Method includes surface cleaning by sand blasting and coating application by detonation method. Coating is obtained from titanium powder with sodium azide azotising additive.

EFFECT: increasing application efficiency, decreasing energy intensity of the process and decreasing substrate heating during coating application.

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Description

The invention relates to methods for applying wear-resistant coatings on the surface of machine parts and can be used in metalworking.

A known method of applying titanium nitride coatings [1], including cleaning the treated surface and vacuum-plasma applying a multilayer coating using reaction gas, while the workpiece is placed in a vacuum chamber equipped with magnetrons, electric arc evaporators and a heater, the treated surface is cleaned in three stage, in the first - in a glow discharge during non-contact heating of the surface by a heater to 100 ° C, in the second - in a magnetron discharge plasma, in the third - wire Ion cleaning is carried out by an electric arc evaporator in an inert gas medium (when the surface is heated to 300-350 ° C), then a lower layer of titanium is applied and alternating layers of titanium nitride and zirconium nitride are applied in a gas mixture of inert and reaction gases.

The disadvantage of the above method is the difficulty of applying thick coatings (tens and hundreds of micrometers) due to the low productivity of the vacuum deposition method used, the high energy consumption of the coating, as well as the need for strong heating of the base material, which can lead to undesirable processes (phase transformations, softening, warpage of the part and etc.).

The method [2] was selected as a prototype, in which the substrate is placed in the vacuum chamber of the installation equipped with magnetron sprays, electric arc evaporators, and a resistive heater, the surface of the substrate is cleaned in a glow discharge when the surface is heated to 100 ° C, and ion cleaning is performed by an electric arc evaporator in a medium inert gas (when the surface is heated to 300-350 ° C), then a lower layer of titanium is applied and alternating layers of titanium nitrides and aluminum are applied, a mixture of inert and reaction gases.

The disadvantage of the above method is the difficulty of applying thick coatings (tens and hundreds of micrometers) due to the low productivity of the vacuum deposition method used, the high energy consumption of the coating, as well as the need for strong heating of the base material, which can lead to undesirable processes (phase transformations, softening, warpage of the part and etc.).

The technical result of the present invention is to increase the productivity of the coating process, reducing the energy intensity of the process and reducing the heating of the substrate during the coating process.

The technical result is achieved by performing surface cleaning and coating of titanium nitride in the reaction gas medium, while cleaning the treated surface by sandblasting, and the coating is applied by the detonation method.

The problem is solved by:

- use to create the coating energy of the explosion of the detonating gas mixture (acetylene 50% oxygen 50%), and not electrical energy, which increases the energy efficiency of the coating process;

- the absence of the need to heat the substrate, which also increases energy efficiency and prevents unwanted thermally activated processes (warpage of the surface, phase transformations, softening, etc.) in the substrate material;

- using the method of detonation spraying, which provides high performance of the coating process (at a frequency of shots up to 10 Hz per layer, a layer with a thickness of up to 10 microns is applied).

The claimed method is implemented in the following steps:

- The substrate is cleaned by sandblasting.

- Prepare a mixture of powders of titanium and sodium azide.

- Apply a detonation coating of titanium nitride using the prepared mixture of powders. The essence of the processes is that during the explosion, sodium azide decomposes with the release of a large amount of nitrogen, which is both a protective and a reaction gas. The titanium particles in the barrel of the detonation installation are heated to the melting temperature and react with nitrogen to form titanium nitride, which is deposited on the substrate in the form of a coating.

Implementation example.

Titanium nitride was coated on a copper substrate using the Dragon automated detonation complex. Nitrogen released during the thermal decomposition of sodium azide was used to carry out the nitride formation reaction.

NaN ₃ → Na + N ₂ + N

The reaction proceeds only with nitrogen released during the decomposition of sodium azide. The calculation of the masses of the components that react with the formation of titanium nitride TiN was carried out according to the equation:

3Ti + NaN ₃ = 3TiN + Na

.The starting components titanium and sodium azide are loaded into the shuttle of the dispenser. The volume of a standard well of the shuttle of the dispenser is equal to V _h = 0.8 · 0.15 · 0.15 = 0.018 cm ³ . The density of the loaded mixture

.

The mass of the loaded mixture is equal to V _h · ρ = 0.0696 g. The mass of titanium powder was determined:

.

.

Thus, a mechanical mixture of powders was prepared based on the ratio m (Ti) / m (NaN ₃ ) = 3.15. Next, 300 shots were performed on a copper substrate. To reduce the influence of the air, the detonation installation barrel was filled with nitrogen at an overpressure of 1.1 atm. The resulting coating had a thickness of 40 μm. The mass of the formed layer is 300 mg. The coating color is black with a yellow coating. As a result, an x-ray phase analysis of the obtained coating was carried out (Fig. 1).

The X-ray diffraction pattern shows that there are no by-products such as sodium oxide and hydroxide in nitrides. Thus, the results of x-ray phase analysis confirmed the possibility of detonation coating of titanium nitride.

Figure 1 shows the x-ray of the obtained coating of titanium nitride.

Figure 2 presents the structure of the obtained titanium nitride coating.

Used Books

1. RF patent No. 2361013. A method of obtaining a wear-resistant coating / V.N. Antsiferov, A.L. Kameneva, A.Yu. Klochkov, R.S. Novikov. Publ. 07/10/2009, bull. No. 19.

2. RF patent No. 2429311. A method of obtaining a coating based on complex nitrides / V.N. Antsiferov. A.L. Kameneva. Publ. 09/20/2011, bull. No. 26.

Claims (1)

A method of producing a titanium nitride coating, including surface cleaning and coating of titanium nitride in a reaction gas medium, characterized in that the surface is cleaned by sandblasting and the coating is applied by a detonation method, wherein the titanium nitride coating is obtained from the initial titanium powder in the presence of a nitriding additive of azide sodium.

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