UA8471U - A method for the laser stimulated electrolytic precipitation of multilayer nickel-phosphorus alloys - Google Patents

Abstract

A method for the electrolytic precipitation of multilayer nickel-phosphorus alloys with pulse current from electrolyte with sodium hypophosphite involves alternation of modes of electrolytic precipitation by pulse current and laser radiation.

Description

Description of the invention

The useful model belongs to the field of applying metal coatings by the laser-stimulated 2 electrolytic method, namely to the field of obtaining multilayer coatings with alloys with different: structure, phase composition, and physical and mechanical properties.

The improvement of the methods of deposition of multilayer films is caused by the need to further improve the quality of the films, increase their protective, decorative and functional properties.

A known method of obtaining multi-layer metal coatings | Declaratory Patent for the invention Mo29691А. 70 Published on November 15, 2000), in which the deposition of multilayer metal coatings takes place by even and odd bursts of pulsed current with a controlled rate of change of cathodic polarization, and during the action of an odd burst of pulsed current, the cathode polarization increases to 4095 from the limit value at a rate of 20V/s and decreases to zero at a rate of ZOV/s.

Disadvantages of this method include the fact that films with high 72 internal stresses are formed during the action of odd packs; the pulsed current reduces the output of metal by the current, which reduces the rate of growth of the thickness of the films.

The method of electrolytic deposition of multi-layer cobalt-phosphorus alloys by pulsed current from an electrolyte containing sodium hypophosphite is the closest in terms of technical essence and the achieved positive result. Declaratory Patent for the invention Mo70562A. Published on October 15, 2004), which consists in the fact that the deposition is carried out by groups of pulsed current alternating with the frequency of current pulses

T1-30-50Hz and the frequency of current pulses in odd groups is 2: 4, in even groups - 216.

But during the action of paired groups (with a sparcity greater than 16), films with high internal stresses are formed, which significantly reduces their functional properties. In addition, the pulsed current reduces the yield of metal by the current, which reduces the rate of growth of the thickness of the films and contributes to the detection of a large number of 29 micropores. -

The technical problem solved by the useful model is: increasing the protective and decorative properties of the films due to the multilayer structure; intensification of the film application process.

The essence of the method of electrolytic deposition of multilayer nickel-phosphorus alloys by pulsed current from an electrolyte containing sodium hypophosphite is that the deposition is carried out by groups of pulsed current - alternating, with a frequency of current pulses of 1-30-50Hz and a sparing of current pulses in odd groups 924 , in even groups - (2216 . The new thing is that deposition is carried out by alternating modes - electrolytic deposition, and in odd groups deposition is carried out by pulsed current, and in even groups by direct current with stimulation of the deposition process by laser radiation.

An example of the method

To obtain Mi-R films, an electrolyte with an additive - sodium hypophosphite - was used. Electrolyte composition, g/l: MiIZO,.7НХО - 300; NUzVOz - 30; Ma»5O, - 50, MaNoRO» - 9, pH-6. In the previously known methods of deposition, it was carried out by direct or pulsed current. The use of pulsed current, which is characterized by high current densities in pulses, large supersaturation values at the crystallization front, and large supersaturation change rates at the crystallization front, contributes to the fact that the crystallization process takes place in strongly unbalanced conditions. y Depending on the frequency (It) and the frequency (C) of the current pulses, different values of supersaturation and the speed of its change are achieved during deposition from the electrolyte of one "" composition at the crystallization front. Therefore, the structure of electrolytic films also changes depending on the frequency and spacing. The use of laser stimulation of electrodeposition with a constant current contributes to the fact that the crystallization process takes place in

Ho) non-equilibrium conditions, which leads to a change in the structure and physical and chemical properties of the films.

Programmable pulsed current was used to obtain multilayer films. Execution of such a program was achieved using direct current instead of even groups of pulses and pulsed current -I frequency of 30-50 Hz with a frequency of less than 4 for odd groups of current pulses. Laser radiation was used to change the conditions of crystallization under 5 hours of the action time of paired groups of pulses. The above-mentioned program ensured the formation of an amorphous-crystalline structure under constant current and the action of laser radiation and the crystal structure under the action of an odd group. As a result, films consisting of alternating layers were formed. The thickness of each layer depended on the duration of the group of current pulses and on the deposition rate for each condition. For odd groups, the deposition rate is 5-bm/h, for

With 55 pairs - 15-18 microns.

A characteristic feature of electrolytic metal films are large internal stresses that appear as a result of twisting of crystal lattices. The latter is caused by a large number of point and line defects. Large internal stresses, often at the limit of strength, lead to the destruction of films, which makes them unsuitable for wide use. The evaluation of internal stresses using the X-ray method showed that micro-layered films have lower values of internal stresses, with high values of microhardness and strength. The absence of microcracks proves a decrease in the value of internal stresses. In addition, layered films have increased protective and decorative properties, because they have practically no intercrystalline corrosion. Data on the conditions for obtaining Mi-R films and their properties are given in Table 1. b5

Table 1

Structure and properties of films

The proposed method 15-18 200-250 4800-5300

The structure of Mi-R films was studied by X-ray structural analysis methods on the DRON-3 installation.

Microhardness was measured with a PMT-3 device when the indenter was loaded at 2Ogr. 70 Thus, the use of the proposed method will make it possible to obtain multi-layer amorphous and amorphous crystalline Mi-R films.

Claims (1)

The formula of the invention y y y y y Method of electrolytic deposition of multilayer nickel-phosphorus alloys by pulsed current from an electrolyte with sodium hypophosphite, which includes deposition by groups of alternating pulsed current, with a frequency of current pulses of 1-30-50 Hz and a splicing of current pulses in odd groups 0-4, in even groups - O x»16, which differs in that deposition is carried out by alternating electrolytic deposition modes, and in odd groups, deposition is carried out by pulsed current, and in even groups - by direct current with stimulation of the deposition process by laser radiation. Official bulletin "Industrial Property". Book 1 "Inventions, useful models, topographies of integrated microcircuits", 2005, M 8, 15.08.2005. State Department of Intellectual Property of the Ministry of Education and Science of Ukraine. - - ich- « (ee) . and? (ee) ChK" - and another 50 So 60 b5