SU1694709A1 - Electrolyte for cathodic chromizing of copper electrolytic foil - Google Patents

Abstract

The invention relates to electroplating, in particular to the electrolytic deposition of chromate films, and can be used in the radio, electronic and other industries related to the manufacture of printed circuit boards. The purpose of the invention is to increase the resistance of the foil to fading. Electrolytic treatment is carried out in an electrolyte containing, g / l: potassium bichromate or sodium 20-30; sodium carbonate or potassium 40-80; aluminum sulphate (on metal) C, 14-0.36; zinc sulfate (on metal) 0.12-0.50; sodium hydroxide or potassium to pH 12-13.5. The process is carried out at room temperature and a cathode current density of 0.1-1 A / dm2. 1 tab

Description

SP

WITH

The invention relates to electroplating, in particular to electrolytic deposition of chromium films, and may find application in the radio engineering, electronic and other industries related to the manufacture of printed circuit boards.

The purpose of the invention is to increase the resistance of the foil to fading at high temperatures.

Electrochemical treatment is carried out in an electrolyte containing, g / l: dichromic-potassium or sodium 20-30; sodium or potassium carbonate 40 - 80; aluminum sulphate

(in terms of metal) 0,14-0,36; zinc sulfate (in terms of metal) 0.12-0.50; sodium or potassium hydroxide to pH 12.0-13.5.

The process is carried out at room temperature and a cathode current density of 0.1-0.1 A / dm2.

As a result of processing in the specified solution, a film is formed on the surface of the copper foil, which includes copper and zinc hydroxocarbonates, hydroxochromates of copper, aluminum and zinc, the presence of which causes the increased resistance of the copper foil to

Qs

Yu

Vj

Oh oh

corrosion and oxidation at elevated temperature (180 ° C).

Specific results illustrating the use of the invention are presented in the table.

Tests for corrosion resistance were carried out in a chamber of heat and moisture (CATV) at 55 ° C and a humidity of 95% for 24 hours.

The anti-tarnish resistance was determined in air at 180 ° C,

As follows from the data presented, the treatment of copper foil in the electrolyte chromate significantly increases its resistance to fading at elevated temperatures and improves its performance properties.

The state of the foil after testing in KW for 0

five

alkali metal oxide, characterized in that, in order to increase the resistance of the foil to tarnish at high temperatures, it additionally contains aluminum and zinc sulfates, and as a dichromate, carbonate and hydroxide of an alkali metal, bichromate, carbonate and sodium or potassium hydroxide respectively, in the following ratio of components, g / l:

Sodium dichromate

or kali 20-30

Sodium carbonate

or Kali 40-80

Aluminum sulphate

(in terms of

on metal) 0,14-0,36

Zinc sulphate

Claims (1)

Claim An electrolyte for cathodic chromating of copper electrolytic foil, 20 containing dichromate, carbonate and alkali metal hydroxide, characterized in that, in order to increase the resistance of the foil to tarnishing at high temperatures, it additionally contains aluminum and zinc sulfates, and as a dichromate, carbonate and alkaline hydroxide or potassium sodium carbonate 20-30 or potassium 40-80 Aluminum sulfate (in terms of metal) 0.14-0.36 Zinc sulfate (in terms of metal) 0.23-0.50 Sodium or potassium hydroxide to pH 12.0-13.5. The electrolyte composition, g / l: foil properties, modes - Example J ’_________ Electrolyte composition Potassium Dichromate 20 - Sodium Bromate - 20 Sodium carbonate 40 - Potassium carbonate , - 40 Sulfate-aluminum 0.14 0.14 Zyk Sulfate 0.12 0.2 Potassium hydroxide to pH 12 Sodium hydroxide. Up to pH - 12 Foil properties The condition of the foil after tests in KVT during 24 h Corrosion Corro not zia no Time to tarnish at heating to 180 ° C, min thirty thirty Soldering ability Good Good Traction strength with electrician, g: source bozo 640 after galvanic processing 585 590 Mode Current density, A / dm ² 1,0 0.6 25 thirty thirty - - - - thirty. 60 - thirty 60 - 80 - - 0.25 oh, zb 0.30 0.2 0.30 0.50 0.45 ο, 3 12.5 13.5 12.0 13.0 Corrosion No- No No not action vie kor- vie kor- corro rosia rosia zii 3 ° thirty zo thirty Good Good Good Good 650 660 620 650 about 600 629 580 610 0.7 0.1 0.5 0.5 Compiled by V. Ignatiev Editor N. Shvydkaya Tehred M. Morgenthal Corrector V. Girnyak Order 4133 Circulation Subscription VNIIIPI of the State Committee for Inventions and Discoveries under the State Committee for Science and Technology of the USSR 113035, Moscow, Zh-35, Raushskaya nab., 4/5 Production and Publishing Combine Patent, Uzhgorod, 101 Gagarin St.