SU905262A1 - Solution for dimensional etching of silver alloy - Google Patents

Description

sr acid dystily glycol at the next; the relative ratio of components, V8C.%: Nitric acid. (beats, weight 1.345 g / cm) 25-35 Glycerin 0.05-0.1 Oxalic acid, 15-25. D f penglycol 0.05-OD Water Other The interaction of octal lettuce ions present in a solution with metal cations leads to the formation of a sparingly soluble precipitate directly on the etching surface, which protects the side edges of the image elements from etching. The etching of a silver alloy in a solution compiled only on the basis of nitric and njsaBelic acid allows half of the reliefs of the image with a density of etching surface not exceeding the 3rd class. The introduction of nitric and oxalic acids into the solution, the addition of glycerol in combination with diethylene glycol, taken in equal amounts, makes it possible to achieve a purity of the etching surface close to the known, i.e. 6th grade. Thus, the surfactants introduced are about: a favorable regulatory effect on the process of capturing, co-formation and the formation of the etching surface. The limiting values of the concentrations of each component in the etching solution are influenced by the influence of their qualitative and quantitative ratio on the etching of the relief images. Thus, the limiting content of nitric acid in the solution, as the main etching agent, is due to the required etching rate of copies of embossed images. The content of nitric acid in the solution below 25 wt.% Does not provide a sufficient rate of etching of the metal, and its content in the solution above 35 wt.% Gives a higher excretion of nitrogen dioxide. The limiting content of oxalic acid in the solution, as the main agent responsible for the formation of an oxalate film, necessary to protect the edges of the relief elements from etching, is indirectly related to the concentration of nitric acid. Only when the ratio of both acids is determined, does the protective oxalate film of the required properties form in the solution. An insufficient content of oxalic acid relative to nitric acid leads to the formation of a loose, fragile film. On the contrary, a relatively high content of Oxalic acid in solution gives too dense (D) / o and a strong oxalate film, which is deposited not only on the lateral faces of the relief elements, but also in areas uncovered with copier layer that prevents etching. In order to achieve the required purity of the etching surface, additions of surfactants glycerin and diethylene glycol in an amount of 0.05-0.1 wt.% Are additionally introduced into the solution of nitric and oxalic acids. Introduction to the etching solution of only one gallchine or diethyleglyco allows to obtain a high purity of etching of the faces of the relief elements, however, in the element of stratification of the sizes of the elements, this exceeds the permissible value. The joint introduction into the solution of nitric and oxalic acids of additives of glycerin and diethylene glycol in the specified amounts allows to obtain the desired purity of the etching surface at an acceptable amount of etching. A solution for size etching of reliefs on silver bars is prepared in the following sequence. .. About 50% of the required volume of water is poured into the bath of the pickling machine, the calculated amount is concentrated. (1,345 g / cm lum 54-57%) nitric acid, added glycerin and diethylene glycol. In a separate container, in 40-50% water of the total volume of the bath at 70-80 ° C dissolve the amount of oxalic acid crystalline hydrate. Pour the dissolved oxalic acid into the pickle, bring the volume of the solution with water to the desired level. Example 1. Artistic images on a silver alloy are obtained by etching copies of patterns on metal in a rotary etching installation using a solution of the composition, wt.%: Nitric acid (specific weight 1,345 g / cm) 25 Glycerin 0.05 Oxalic acid 15 Diethylene glycol 0.05 Water Else Rend etching: Rotational speed of rotors, rpm550 Solution temperature, ° С 40 Time, min25 Relief etching depth 300 µm. The angle of inclination of the side facet of the relief elements at the height is 28 °. Purity of 5th grade etched grazing, 23mkm bleed. Example 2. Etching of copies of patterns on an alloy of silver is carried out in an etching installation using the etching mode described in Example 1. A solution of the composition, wt.%, Is used: Nitric acid (specific weight 1,345 g / cm) 30 Glycerin 0, 08 Oxalic acid20

Glycol 0.08

Water- Rest

The etching depth of the relief is 370 microns. The angle of the side facet of the relief elements at the top of the image element is 18 °. The purity of the etched surface is of the 6th class. Bleeding 28 microns.

PRI me R 3. The etching of copies of patterns on a silver alloy is carried out in an etching installation under the etching mode described in Example 1.

Use the solution composition, wt.%:

Nitric acid

(beats weight 1,345 g / cm) 35

Glycerol 0.1

Oxalic acid25

Diethylene glycol 0,1

WaterEverything

The etching depth of the relief is 450 microns. The angle of inclination of the side face of the relief elements at the top of the image element is 12 °. The etched surface is 6 grams cl. Grade; etching is 34 µm.

The use of the solution for dimensional etching of reliefs on silver alloys with the use of manual engraving of relief images will provide a significant economic effect from its introduction into production, increase labor productivity by a factor of 7–10 and organize the mass production of relief images.

Claims (2)

1. Conducting photolithography. Ed. V.P. Lavrisheva, M., Energie, 1977, p. 232 2. Introduction to photolithography. Ed. V.P. Lavrishcheva, M., Energie, 1977, p. 232 (prototype).