SU850764A1 - Solution for electrochemical polishing of titanium - Google Patents

Description

(54) SOLUTION FOR ELECTROCHEMICAL POLISHING

one

The invention relates to the electrochemical treatment of metals (ECM), in particular to the polishing of titanium foil, for example BT-1-0.

Known aqueous solution for titanium ECHO containing,% by volume: Sulfuric acid 20 Hydrofluoric acid1 Nitric acid 4 Water 75

However, this solution is intended to remove scale from the monolithic tich. And, in this case, the product is a cathode. The use of this solution for polishing thin titanium foil does not give a positive effect, since a strong etching of the surface occurs in an aqueous solution of an acid mixture.

Closest to the proposed effect achieved is a solution for electrochemical polishing of titanium, containing sulfuric (80-85%) and hydrofluoric (1018%) acids, as well as water, and intended for polishing monolithic titanium G21.

TITAN

However, this aqueous solution of acids is also unsuitable for polishing a thin foil due to the poor quality of polyurethane, since a strong etching occurs at the surface of the fbetigi and destroys it at the solution – air interface until it is completely dissolved due to a large metal removal.

ten

The purpose of the invention is to improve the quality of polishing with a slight removal of metal.

This goal is achieved by the fact that the solution additionally contains

15 nitric acid in the following ratio of components, vol.%: Sulfuric acid, 37-41 Hydrofluoric acid 18-22

20 Nitric acid 40-41 Nitric acid has a passivating effect and prevents the foil from etching the surface, making it evenly polished.

25

The polishing process is carried out at 20-25 ° C, anode current density of 120150 mA / cmH voltage 4V, for 4-5 minutes. At a given mode, prsis30), the minimum metal removal

f, 0024 g / cm at the initial thickness (foil 0.01-0.015 mm.

The solution is prepared as follows.

f

To concentrated sulfuric acid (spd. 1.84), while slowly mixing hydrofluoric acid (sp. 1.15) is added, to the resulting mixture, cooled to 20SS c, nitric acid (sp. 1,4). The solution is stable when passing

777.6 Ah / l.

After polishing, the foil is washed in running tap water, then in distilled water, and dried under nitrogen at a C – O С level for 10–15 min.

The table shows the composition of the proposed solution and the mode of surface treatment of titanium foil.

Thus, replacing water in a known solution with nitric acid allows polishing the surface of the titanium foil to a high purity grade (10–12) with a relative brightness of 80–90% and a slight metal removal.

Claims (2)

Claim A solution for electrochemical polishing of titanium, mainly titanium Foil, containing sulfuric and hydrofluoric acids, characterized in that, in order to improve the quality of polishing with a slight removal of the metal, it additionally contains nitric acid in the following ratio of components, vol.%: Sulfuric acid37-41 50 Hydrofluoric acid 18-22 Nitric acid 40-41, Sources of information taken into account during the examination 55 1. US patent No. 2780594,. class 204-141, published. 1957. 2. Popilov L.Ya. and Zaitseva L.P. Electropolishing and electrical etching of metallographic sections. M., Metallurgizdat, 1963, pl. 3. VNIIIPI Order 6259/37 Circulation 704 Subscription Branch of the PPP Patent, Uzhgorod, Project 4,