RU2630162C1 - Method for producing co-p amorphous films on dielectric substrate - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to chemical deposition of magnetically soft and magnetically rigid films of cobalt-phosphorus composition used as media for magnetic and thermomagnetic recording for the creation of microelectromagnetic mechanical sensors (MEMS), as well as in sensors of weak magnetic fields, in microwave devices: filters, power limiters, amplitude modulators, phase manipulators. The method includes cleaning the dielectric substrate, double sensitization in a solution of tin chloride, activation in a solution of palladium chloride, and precipitation of a Co-P magnetic film. In this case, between the stages of sensibilization, heat treatment is carried out at a temperature of 300-450°C, and the deposition of the Co-P magnetic film is carried out on the dried substrate from a solution containing, g/l: cobalt sulfate CoSO₄⋅7H₂O - 10, sodium hypophosphite NaH₂PO₂⋅H₂O - 7.5, sodium citrate Na₃C₆H₅O₇ - 25, at 95-100°C and pH of the solution from 7.1 to 9.6, which is set by adding alkali to the solution.

EFFECT: production of both high-coercivity and low-coercivity Co-P films and simplification of the technology by reducing the number of technological operations.

1 dwg, 1 tbl

Description

The invention relates to the field of chemical deposition of soft and hard magnetic films of the composition of cobalt-phosphorus, used as media for magnetic and thermomagnetic recording, to create microelectromagnetic mechanical devices (MEMS), as well as in sensors of weak magnetic fields, in microwave devices: filters, power limiters amplitude modulators, phase manipulators.

Existing methods for producing Co-P magnetic films by chemical deposition on glass substrates include the steps of chemical cleaning, sensitization, activation, and precipitation from solutions using sodium hypophosphite as a reducing agent. To improve the quality of films (adhesion, magnetic and other properties), various types and modes of preliminary chemical and heat treatment of glass, various compositions of solutions with the addition of salts of mainly organic acids, etc. are used [K. Vansovskaya Chemical Coatings / Ed. P.M. Vyacheslavov. - L .: Engineering, Leningrad. Department, 1985. - 103 p., ill. (B-galvanic engineering; Issue 7].

Closest to the claimed invention in technical essence and the achieved result is a method for producing magnetic films Co-P with preset values of coercive force H _C [patent 2501888, IPC С23С 18/18, publ. December 20, 2013 (prototype)], including cleaning the substrate, double sensitization in a tin chloride solution with intermediate treatment in a hydrogen peroxide solution, activation in a palladium chloride solution, heat treatment at a temperature of 150-450 ° C for 30-40 min, precipitation Co-P magnetic film on a non-magnetic amorphous Ni-P layer with a thickness of 20-30 nm when a uniform magnetic field is applied in the film plane, while a non-magnetic amorphous Ni-P layer from 2.0 to 6 thick is additionally deposited on the Co-P magnetic film, 0 nm followed by deposition of an identical Co-P films.

However, the prototype method is difficult to implement and does not provide highly coercive films.

The technical result of the invention is to obtain both highly coercive and low coercive Co-P films and simplify the technology by reducing the number of technological operations.

The technical result is achieved by the fact that in the method for producing amorphous Co-P films on a dielectric substrate, including cleaning the substrate, double sensitization in a tin chloride solution, activation of a palladium chloride solution and deposition of a Co-P magnetic film, the new thing is that between the sensitization steps conduct heat treatment at a temperature of 300-450 ° C, and Co-P magnetic film is deposited on a dried substrate from a solution containing, g / l: cobalt sulfate COSO ₄ ⋅ 7H ₂ O - 10, sodium hypophosphite NaH ₂ PO ₂ ⋅H ₂ O - 7.5, sodium hydroxide minutes citrate Na ₃ C ₆ H ₅ O ₇ - 25, at 95-100 ° C and pH 7.1 to 9.6, which is set by adding alkaline solution.

In FIG. 1 shows the dependence of the coercive force on the concentration of NaOH.

The following describes an example of a specific implementation of the proposed method, accompanied by 1 table. and FIG. one.

The preparation of the substrates before applying Co-P is as follows:

1) cleaning from greasy contaminants with a detergent for dishes and accessories, followed by washing in a stream of distilled water at a speed of 5-10 ml / s, T = 20-30 ° C, t = 30 s;

2) holding in HSP nitric acid HNO ₃ saturated with potassium dichromate K ₂ Cr ₂ O ₇ for 20 hours at T = 20-30 ° C, followed by washing in a stream of distilled water at a speed of 5-10 ml / s, T = 20 -30 ° C, t = 30 s;

3) holding in a SnCl ₂ solution for 120 s, followed by washing in distilled water for 120 s at T = 95-100 ° C, followed by washing in a stream of distilled water at a speed of 5-10 ml / s, T = 20-30 ° C, t = 30 s. The SnCl ₂ solution is prepared as follows: 100 mg of SnCl _{2 is} dissolved in 300 ml of distilled water, heated to 95-100 ° C and maintained for 15 minutes. After cooling to T≤50 ° C, the solution is filtered through a double filter of the class "blue ribbon";

4) heating the substrate to T = 300-400 ° C in air with exposure for 120 s, followed by washing in a stream of distilled water at a speed of 5-10 ml / s, T = 20-30 ° C, t = 30 s;

5) aging in a solution of SnCl ₂ similarly to paragraph 3;

6) holding in a solution of PdCl ₂ for 120 s, followed by washing in a stream of distilled water at a speed of 5-10 ml / s, T = 20-30 ° C, t = 30 s. A solution of PdCl ₂ is prepared as follows: 0.5-1 g of PdCl ₂ and 12-18 g of HCl are dissolved in 1 liter of distilled water;

7) drying the substrate at T = 60-80 ° C until completely dry.

Co-P with a thickness of 100 nm was deposited on a glass substrate prepared by this method with a size of 16 × 16 mm and a thickness of 0.17-0.19 mm (cover glass). Precipitation is carried out from the solution, in g / l: cobalt sulfate CoSo ₄ ⋅ 7H ₂ O - 10, sodium hypophosphite NaH ₂ PO ₂ .H ₂ O -7.5, sodium citrate Na ₃ C ₆ H ₅ O ₇ - 25, at T = 95-100 ° C.

The pH value required to obtain the necessary coercive force of the films is set in accordance with Table. 1 addition of alkali (NaOH or KOH).

From the table. 1 it can be seen that the coercive force of the films is directly dependent on the concentration of the pH of the reduction solution, which allows one to obtain both high and low coercive films with specified values of the coercive force in a wide range.

This method can be successfully used to obtain both crystalline high-coercive (H _C > 100 O) and nanocrystalline low-coercive (H _C <100 O) films not only on polished glass, but also on other dielectric materials, for example, polycor, ceramic, quartz .

An important advantage from the point of view of simplifying the organization of the process is:

1) the use of solutions with a minimum number of components;

2) the absence in the solution of such volatile components as ammonia, which helps to preserve the properties of the solution over time;

3) the production of single-layer films with broadly defined values of the coercive force from solutions that differ only in pH value.

Claims (1)

A method of producing amorphous Co-P films on a dielectric substrate, including cleaning the substrate, double sensitization in a tin chloride solution, activation of a palladium chloride solution and deposition of a Co-P magnetic film, characterized in that heat treatment is carried out between sensitization steps at a temperature of 300-450 ° C, and the Co-P magnetic film is deposited on a dried substrate from a solution containing, g / l: cobalt sulfate CoSO ₄ ⋅ 7H ₂ O - 10, sodium hypophosphite NaH ₂ PO ₂ ⋅H ₂ O - 7.5, sodium citrate Na ₃ C ₆ H ₅ O ₇ - 25, at 95-100 ° С and pH of races a creator from 7.1 to 9.6, which is set by adding alkali to the solution.

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