SU722865A1 - Pickling solution - Google Patents

Description

one

The invention relates to the technology of processing phosphate sitoplov and glasses and can be used in the optical-electronic industry in the manufacture of optical components.

A known pickling solution for matting is surfaced of glass-ceramic materials and glass containing hydrofluoric acid, sulfuric acid, potassium chloride and distilled water. I.

However, these solutions are mostly applicable to silicate glass-ceramic materials and glasses that are less resistant to hydrofluoric acid. Phosphate sitalls and glasses, more resistant to hydrofluoric acid, in these solutions are etched at a low speed, and in some cases the etching is stopped due to the formation of an insoluble salt film on the surface of the product. In this case, it is impossible to achieve even matting of the surface due to uneven etching of the phase

components of phosphate sitalls and glasses, which prevents the achievement of high strength characteristics.

The closest to the invention is an etching solution 2 comprising the following ingredients, wt%: Hydrofluoric acid 10 N nitric acid 4 O

Acetic acid30

Water the rest to

1OO%

The presence of an organic additive makes it possible to regulate the etching process.

However, when processing phosphate cellars and glass in a solution of this composition, a salt film is formed (products of etching reaction), which firmly adheres to the surface of the processed products, which leads to a sharp decrease in the rate of chemical etching due to poor supply of fresh solution. The speed of chemical treatment of phosphate cellars and glasses in this solution is O, O5 µm / min, which complicates the technology for processing products of these glass-ceramic materials and glasses. As a result, it is impossible to obtain a uniformly matte surface due to the formation of micro unevenness caused by the uneven bleeding of the phase components of phosphate cellars and glasses; in addition, the treated products are characterized by insufficient mechanical strength.

The aim of the invention is to improve the etching rate and the mechanical strength of the treated glass and glass ceramics.

The goal is achieved by the fact that the pickling solution, including hydrofluoric acid, nitric acid and water, contains polyacrylamide as an orgshchnic additive in the following ratio of components, wt.%:

Hydrofluoric acid 50-6 O Nitric acid 2 O-ZO

Polyacrylamide

1-5

The rest is up to 1%

Example. Solutions are prepared by mixing aqueous solutions of inorganic 1HSLOT with an aqueous solution of polyacrylamide. To determine the etching rate, mechanical strength, roughness, samples were made of a phosphate cellar of the brand CO 11575 with a size of 10x10x120 mm. The surface of the samples is processed on an optical machine DM-2 using the free abrasive method. The size of the etched layer is determined with a micrometer, the time of etching with a stopwatch. The mechanical strength was determined at the bend test of the indicated samples according to the three-point loading pattern. The surface roughness is determined by an M201 profilograph-profilometer.

The results of the comparative tests are shown in the table.

Known solution 0, О51,0-0,6 Offered Hydrofluoride 0,502,5 acid 5О Nitric acid 2О Polyacrylamide 1 Water Else Up to 100;% Hydrofluoric acid 55 Nitric acid 25 Polyacrylamide 3 Water Else up to 1OO% Hydrofluoric acid 60 Nitric acid 30 Polyacrylamide 5 Water Else up to 100%

Claims (2)

Observed individual etching defects in the form of protrusions and wet, lack of a uniformly matted surface 0.60, 2 holes 10 Evenly matted surface is observed 14 The optimum combination of sample properties after processing 114 Surface (Not enough matted From the results of comparative tests it can be seen that the decrease in the minimum content of solution components ( including polyacrylamide less than 1%) does not lead to a significant increase in strength. With a further increase in the maximum number of components of the solution (including polyacrylamide more than 5%) is not achieved effective matting of the surface. The optimal composition of the pickling solution for the treatment of phosphate salts and glasses contains the following ratio of components, wt.%: Hydrofluoric acid (7O%) Nitric acid Polyacrylamide (8%) Else The presence of a surfactant polyacrylamide in the solution makes it possible to regulate the quality of matting. At low levels, polyacrylamide is adsorbed on the active pax of the treated surface, preventing and portions of the effective herbs laziness. The surface areas not blocked by the buffer additive (house polyacrylics) are etched with greater speed. This etching produces a uniformly matted surface. With high contents of surfactant vocet (polyacrylamide), the entire treated surface is fully protected from intense etching. In such a solution, the etching proceeds more smoothly, the surface is smoothed and there is no intensive matting. The presence of a film-forming substance (polyacrylo shda) in the composition reduces the evaporation rate of fluoride of water 656 of the genus, which improves working conditions and both.:. preservation of the composition of the pickling bath. The use of the described solution for the treatment of phosphate sitoples and glasses allows an increase in the rate of chemical etching 5–1O times, which will facilitate the treatment of phosphate sitalls and glasses; improve the quality of the surfaces to be treated with uniform matting; increase the mechanical strength of the processed products from phosphate sitalls and glasses; reduce the evaporation rate of hydrogen fluoride, which will improve the working conditions and ensure the safety of the pickling solution. The invention of the etching solution, mainly for the treatment of phosphate glasses and sitals, including hydrofluoric acid, nitric acid, an organic additive and water, characterized in that, in order to increase the rate of etching and mechanical strength of the treated glasses and sitals, it contains as much as an organic additive polyethylene acrylamide The following ratio of components, wt.%: Hydrofluoric acid 50-6 O Nitric acid 2 O-30 Polyacrylamide 1-5 Water Else Information source taken into account during the examination e 1.Avtorskoe communication) vdetelstvo USSR 22O451 K, Cl. S OZ S 15 / OO, 1967. 2.Patent UK No. 1217О50, cl. In 6 Oe, 197O.