CS271852B1 - Electrolytic method for metallic materials' surface degreasing's operating determination - Google Patents

Abstract

The electrolytic method regarding operational estimation for degreasing surfaces of metal materials such as copper, brass, aluminium, nickel and chrome is designed for the operational estimation of complete degreasing in surface treatment operations. The test is non-destructive and this procedure enables monitoring of correct function of the chemical and electrolytic degreasing bath. The test is brief and reliable and lasts no more than ten minutes. The bath is not toxic and the elimination of sewage water is carried out by mere neutralizing. The estimation is carried out by mere dipping in the bath - the chemical composition of which is included in the description - and by connecting to the EMS, or by providing contact from steel or zinc.

Description

(54) Electrolytic method for the operational determination of degreasing of metal surface (57) The electrolytic method of the operational determination of degreasing of the surface of metallic materials such as copper, brass, aluminum / nickel and chromium is intended for the operational determination of degreasing perfection in surface treatment plants. The test is non-destructive and the procedure can monitor the proper functioning of chemical and electrolytic degreasing baths. The test is fast and reliable and takes up to 10 minutes. Climbing is not toxic and wastewater disposal is simply neutralized. The determination is carried out by simply immersing in a bath whose chemical composition is described and connected to an EMS, optionally by contacting steel or zinc.

CS 271852 Bl

CS 271 852 Bl

The invention relates to an electrolytic process for the operational determination of surface degreasing of metallic materials such as copper, brass; nickel, chrome; aluminum, etc., by means of color coatings, 'formed by electrolytic reduction in aqueous solutions of sodium or ammonium molybdate on the surfaces of the metal materials to be monitored.

The method used to determine degreasing and / or grease for operational purposes so far is cited as a method of breaking a continuous water film. It is not possible to evaluate the areas 10 mm from the edges e sharp edges and it is not possible to evaluate any cavities, depressions or joints. The articulated and intricately geometrically shaped objects cannot be so reliably evaluated. Only flat surfaces can be evaluated by the method and a comparative sample is required. Whose production is lengthy and laborious.

The above problem solves the invention. The principle is that the metal material is connected as a cathode and immersed in an aqueous solution of sodium or ammonium molybdenum at a concentration of 2.0 g / l to 100.0 g / l in the presence of a conductive salt such as sodium siren, * acetate sodium or foefornene sodium at a concentration of 2.0 g / l to 20.0 g / l. The pH of the solution ee is adjusted to a range of 1 to 6 to 6 using acetic acid; sirové; hydrochloric or phosphoric. The anode ee selects stainless steel or lead rod. It is electrolyzed at a current density of 0.01 A / dm ² to 3.0 A / dm ² for 1 to 10 minutes and a solution temperature of 20 ° C to 70 ° C. Good degreasing results in the formation of a solid, iridescent coating from yellow to violet and green to brown to black that is different from the base metal. · In the case of imperfect degreasing, stains will occur after drying and wiping with a dry cloth.

The same electrochemical process and the same effect occurs when the metal material is provided with a steel or zinc contact, where the contact acts as an anode. In this case, the bath temperature is selected above 40 ° C.

The resulting colored coating is contracted by dipping in 20% by weight. concentration of hydrochloric acid and used metal material Can be further used in the production process. The test also includes corroding and crosslinking of the metal surface; which can be reliably removed by soaking in 30% (w / w) hydrochloric acid concentration before carrying out the test.

The test is suitable for operational testing of the effect of chemical and electrochemical degreasing baths, where the problems of metal surface treatment begin. The test is very sensitive to sweat of hands and because it works in gloves or with tweezers.

Example 1 1 g of sodium molybdate aa is dissolved in 500 ml of water and aa 20 g of sodium sulphate is added. After making up to 1 liter, the pH of the bath is adjusted to 5/0 with 5 wt. Sulfuric acid concentration · After stirring for 5 minutes, the solution is left to stand and then immersed in the test item (nickel-plated or copper-plated steel) and plugged in as a cathode and anode.

Claims (2)

selects stainless steel · At a bath temperature of 20 ° C ee selects a current density of 0/3 A / dm ² and an exposure time of 2 to 4 minutes. The object rotates freely or selects multiple anodes around the metal object. · After staining, the test metal object is rinsed with water, allowed to drip, and wiped with a dry cloth. Oobró degreasing ae manifested by formation of a solid rainbow color; which is different from the color of the parent metal · If the metal surface is greased, stains will appear where the parent metal color is translucent. The method is very sensitive 1 to hand sweat e use e! gloves or tweezers. The surface passage of the metal ea is removed by pickling in 30% by weight of the hydrochloric acid concentration for 5 minutes (ee for older samples). Example 2 Dissolve 70 g of ammonium molybdate in 500 ml of water and add ee 10 g of sodium citrate. After making up to 1 liter and adjusting the pH of the bath to 4.0 to 4.5 with 10 wt. concentration of acetic or hydrochloric acid. Oo baths and e dip an aluminum object soaked in 40 wt. The electrolysis is carried out at a bath temperature of 20 ° C for 1 to 2 minutes at a current density of 1.5 A / dm ² to 2.5 A / dm ² . CS 271 852 Bl After rinsing, β wiping ee evaluates as in Example 1. Example 3 Dissolve 20 g of sodium bicarbonate in 500 ml of water β add ee 20 g of sodium hypophosphite. After the addition of ηβ 1 liter, the pH of the bath is adjusted to 3, 5 with 40% by weight. concentration kyeellny fos foratory. The bath is heated to 60 ° C and immersed in the metal object to be tested (nickel-plated steel or brass) and the metal object is provided with a steel wire contact. The exposure time is selected in the range of 4 to 6 minutes. The evaluation and removal of passivity is carried out as in Example 1. Waste water disposal services; because the bath is not toxic; is done by mere neutralization. * All samples not tested for deficiency; it is possible to remove the colored coating by pickling in 20 wt. concentration of HCl used further in production. The test does not destroy the sample. SUBJECT OF THE INVENTION 1. An electrolytic method for the operational determination of surface degreasing properties of metallic materials, such as copper; brass, ¹ aluminum; Chromium and silver based on individual metal colorings, characterized in that the metal material is immersed in an aqueous solution of sodium or ammonium molybdate at a concentration of 2.0 to 100.0 g / l in the presence of a hydrous salt such as sodium acetate , sodium sulphate or sodium hypophosphite at a concentration of 2; 0 to 20 .mu.g / l and the pH of the solution is maintained in the range of 1.5 to .beta. using acetic acid, sulfuric acid; hydrochloric or phosphoric and the electrode is used as a cathode and an anode of stainless steel or lead bar and electrolysis are selected at a current density of 0.01 A / dm ² to 3f0 A / dm ² for 1 to 10 minutes at a bath temperature of 20 ° C to 70 ° C. 2. An electrolytic method for the operational determination of metal surface surface scavenging according to claim 1; that the DC metal material contacts a steel or zinc contact; having an anode function and immersed in a bath at a temperature greater than 40 ° C.