RU2167113C2 - Method of chemical nickel plating of glass - Google Patents

Abstract

FIELD: preparation of both functional and decorative nickel coatings. SUBSTANCE: method comprises etching, washing after etching, activation and metallization activation being carried out in tin II salt solution with concentration of 0.20-0.30 mole/l at room temperature for 5-10 min, and glass product with tin II chloride remnants is thereafter treated for 5-10 min with solution of reducing agent such as sodium hydroxymethane sulfinate or thiourea dioxide with concentration of 0.2- 1.0 mole/l at 60-80 C, and metallic nickel is then deposited chemically onto activated glass surface at 60-80 C for 10-15 min in bath containing components, mole/l: sodium hydroxymethane sulfinate of chioureau dioxide, 0.2-1.0; ammonia nickel complex, 0.1-0.15; acetone, 0.002-0.02; distilled water, up to 1 l. EFFECT: nickel coating having higher metal content and simplified process. 2 cl, 6 ex

Description

 The invention relates to methods for chemical metallization of glass surfaces and can be used to obtain both functional and decorative nickel coatings.

 The known method of chemical metallization of glass includes successive stages of surface pretreatment: degreasing in an aqueous alkali solution at pH <13, treatment with a tin salt solution, activation with an aqueous solution of palladium salt, and, in fact, the metallization process in a solution containing approximately equal amounts of ethyleneamine, salt nickel and sodium phosphite salts [Pat. Japan N 142514 C 03 C 25/04 dated 02.25.85].

A known method of producing a metal coating of nickel and its alloy with phosphorus and boron on glassware is the restoration of nickel salts with sodium hypophosphite or sodium borohydride in an aqueous solution at pH 5.0 after a preliminary etching of glass HF (acid), sensitization with a solution of tin (II) chloride (SnCl ₂ ) with hydrazine and activation with a noble metal (gold or palladium). [Pat. England N 1246966 C 23 C 3/02 dated 09/22/71].

 The disadvantage of these methods is the high cost of the activating solution (salts of palladium and gold). In addition, the most commonly used reducing agents, such as sodium borohydride, hydrazine, sodium hypophosphite, are characterized by low stability and low inflammability of gaseous decomposition products. Metal coatings obtained using the above reducing agents are contaminated with solid decomposition products (phosphorus in the case of sodium hypophosphite or boron in the case of sodium borohydride), which in some cases reduces the content of the base metal in the coating and degrades the performance of the coating.

A known method of producing a Nickel coating on materials from carbon fibers [US Pat. Russia N 2063461 from 07/10/96]. The method is implemented as follows. The surface of the carbon fiber (HC) product is subjected to etching for 6 minutes at a temperature of 60 ^° C. with a 0.3 M solution of potassium dichromate in concentrated (d = 1.83 g / cm ³ ) sulfuric acid, after which the product is not washed with etching residues surface mixtures are immersed in a metallization bath with an aqueous solution of sodium hydroxymethanesulfinate or hyaurea dioxide and nickel chloride. The duration of this stage is 3 minutes at 80 ^o C, after which the product is washed with water and dried. The proposed method produces matte and shiny coatings of nickel on carbon fiber with a layer thickness of 4.5-5.2 μm at an average metallization rate of 24 μm / h.

 The modes of this process do not allow to obtain a nickel coating on the glass.

Closest to the proposed invention, that is, the prototype, is a method with palladium-free activation in the processes of metallization of glass and glassware. A porous, activated high-silica film is created by etching glass heated to 100-250 ^° C with HF vapors. After washing, the etched surface is activated with a solution of nickel or cobalt salt at pH 5-6, followed by reduction of the metal on the glass surface with potassium borohydride. Then metallization is carried out directly in a bath with a salt of the metal to be released, with hypophosphite ions and a salt of carboxylic acid at a temperature of 95-100 ^o C. It is possible to obtain coatings up to 1 μm thick. [Pat. England N 896177 from 05.05.62].

 The disadvantage of the prototype is the use as an etching agent of vapors of aggressive hydrofluoric acid, as well as the complexity of the composition of the activating solution. As in the analogs, the prototype uses reducing agents, which, when decomposed, produce toxic explosive gaseous products in the exhaust gases, the cleaning of which requires significant additional costs. Solid decomposition products of reducing agents contaminate metal coatings and often degrade their consumer properties. The prototype method also uses high temperature conditions, which lead to higher prices for the final product.

 The objective of the invention is to provide a method for chemical nickel plating of glass, which allows to obtain a nickel coating with a higher metal content, to simplify the process technology, lower the temperature of the etching operations and metallization itself, as well as reduce the cost of sanitary and environmental measures by reducing the toxicity of the exhaust gases from the etching baths, activation and metallization with increasing thickness and maintaining the adhesive properties of the coating.

The problem is solved by the proposed method of chemical nickel plating of glass, including etching, washing after etching, activation and, in fact, metallization, in which activation is carried out in a solution of tin (II) salt with a concentration of 0.20-0.30 mol / l at room temperature in within 5-10 minutes After that, the glassware with the remains of a solution of tin (II) chloride is treated for 5-10 minutes with a solution of a reducing agent - sodium hydroxymethanesulfinate (HMS) or thiourea dioxide (DOTM) with a concentration of 0.2-1.0 mol / l at a temperature of 60-80 ^o C. On the glass surface thus activated, metal nickel is chemically precipitated for 10-15 minutes at 60-80 ^° C in a metallization bath of the following composition, mol / l:
Sodium hydroxymethanesulfinate or thiourea dioxide - 0.2-1.0
Nickel ammonia complex - 0.1-0.15
Acetone - 0.002-0.02
Distilled Water - Up to 1 L
In conclusion, the glass product is washed with water and dried. The proposed method can be obtained matte and shiny coatings of Nickel with a layer thickness of 0.5-1.2 μm with an average metallization rate of 2-5 μm / h. If necessary, the thickness of the metal coating on the glass can be increased by known electrochemical methods.

 Example 1

The product from building silicate glass is etched for 40 min at a temperature of 70 ^o C in a mixture of potassium dichromate (0.3 M) and concentrated (d = 1.83 g / cm ³ ) sulfuric acid, and then washed with water from the rest of the etching mixture first tap and then distilled water. Then, for 10 min at room temperature, they are kept in a solution of tin (II) chloride with a concentration of 0.2 mol / L. Then, the product is treated for 10 min at 60 ^° C with a solution of sodium hydroxymethanesulfinate with a concentration of 0.2 mol / l, and then without washing, it is placed in a metallization bath with a solution containing nickel ammonia complex (0.1 mol / l), sodium hydroxymethanesulfinate (0, 2 mol / L) and acetone (0.002 mol / L). The metallization time is 15 minutes, the temperature is 60 ^o C. A uniform, smooth, shiny coating with a layer thickness of 0.5 μm, which adheres well to glass, is obtained.

 Example 1a

 The technological process is similar to example 1. As a reducing agent, thiourea dioxide (0.2 mol / l) is used. It turns out a uniform, smooth, shiny coating with a layer thickness of 0.55 microns, which adheres well to glass.

 Example 2

The borosilicate glass article was etched for 15 minutes in a 3.0 M KOH solution at 70 ^° C. The etched article was washed with water and immersed for 10 minutes in a tin (II) chloride solution with a concentration of 0.25 mol / L at room temperature. Next, the glass surface is treated with a solution of sodium hydroxymethanesulfinate (0.5 mol / l) for 7 min at 70 ^° C and the glass product is placed in a metallization solution containing an ammonia complex of nickel (0.1 mol / l), sodium hydroxymethanesulfinate (0, 5 mol / L) and acetone (0.01 mol / L). The metallization time is 15 minutes, the temperature is 70 ^o C. A uniform, smooth, shiny coating is obtained with a layer thickness of 0.58 μm, which adheres well to glass.

 Example 2a

 The technological process is similar to example 2. Thiourea dioxide (0.5 mol / l) is used as a reducing agent. It turns out a uniform, smooth, shiny coating with a layer thickness of 0.65 μm, which adheres well to glass.

 Example 3

The product from technical silicate glass is etched for 40 minutes at a temperature of 70 ^o C in a mixture of potassium dichromate (0.3 M) and concentrated (d - 1.83 g / cm ³ ) sulfuric acid, after which it is washed first with tap water and then with distilled water from the remains of the etching mixture. Next, the product is immersed for 5 min at room temperature in a solution of tin (II) chloride with a concentration of 0.30 mol / L. A glass product with the remainder of the tin (II) chloride solution without washing is placed in a 1.0 M sodium hydroxymethanesulfinate solution at a temperature of 80 ^° C. for 5 minutes. Then the glass product is immersed without washing in a metallization solution containing an ammonia complex of nickel (0.15 mol / L) and sodium hydroxymethanesulfinate (1.0 mol / L) and acetone (0.02 mol / L). Metallization time 10 min, temperature 80 ^o C. A uniform, smooth, glossy coating with a layer thickness of 0.85 μm, which adheres well to glass, is obtained.

 Example 3a

 The technological process is similar to example 3. As a reducing agent, thiourea dioxide (1.0 mol / l) is used. It turns out a uniform, smooth, shiny coating with a layer thickness of 1.2 microns, which adheres well to glass.

 Using the proposed method provides the following advantages in comparison with the prototype: improving the quality of the coating by increasing the content of the deposited metal up to 99.9% by weight while increasing the thickness to 1.2 microns and maintaining the adhesive properties of the coating, reducing the cost of the process by reducing the number of toxic reagents and lowering the temperature regimes of recovery processes and metallization itself. In addition, the method allows to improve the sanitary and environmental characteristics of production by reducing the toxicity and fire hazard of the components of the pickling, activation and metallization baths.

Claims (1)

A method of chemical glass nickel plating, including etching, washing, activation and metallization, characterized in that the activation is carried out in a solution of tin (II) salt, followed by treatment with a solution of sodium hydroxymethanesulfinate or thiourea dioxide with a concentration of 0.2-1.0 mol / l at 60 - 80 ° C for 5-10 minutes, and metallization is carried out at the same temperature for 10 - 15 minutes in a solution of the following composition, mol / l:
Sodium hydroxymethanesulfinate or thiourea dioxide - 0.2-1.0
Nickel ammonia complex - 0.1-0.15
Acetone - 0.002-0.02
Distilled Water - Up to 1 L