Zinc electroplating

Yet another option for domestic appliances is to make the appliance from precoated coil. The appliance has to be designed to minimise the problem of unprotected cut edges. Electroplated zinc-coated steel, pretreated, primed and finished with special polyester-melamine, is used. The finish is designed to be hard at room temperature, yet accept bending and forming, probably, but not necessarily, at somewhat higher temperatures (ca. 60°C). 

What conditions work best for electroplating zinc onto a metal object Does changing the current affect the quality of the finished object ... 

Design a procedure to electroplate zinc onto the metal object you have chosen. You will repeat your procedure three times, using three different values for the current, and three different metal objects. 

Compare the three finished objects that you electroplated. What conditions worked best to electroplate zinc onto a metal object ... 

Zinc. Suppliers of zinc electroplating chemicals have reported that zinc electroplating volumes continue to grow. More recently, electroplated zinc alloys have been promoted. Zinc was priced at 1.50/kg in early 1993 (see Zinc and zinc alloys). 

In zinc electroplating, zinc ions are reduced to zinc atoms at the surface of the metal object to be coated, which becomes the cathode in an electrolytic cell. At the anode, which is made of zinc, atoms of zinc are oxidized to ions. The electrolyte solution contains dissolved zinc salt. 

N.R. Short, A. Abibsi, J.K. Dennis, Corrosion resistance of electroplated zinc alloy coatings, Trans. Inst. Met. Finish. 67 (1991) 73-77. 

D.H. Coleman, G. Zheng, B.N. Popov, R.E. White, The effects of multiple electroplated zinc layers on the inhibition of hydrogen permeation through an iron membrane, J. Electrochem. Soc. 143 (1996) 1871-1874. 

Insoluble lead anodes have been used for electroplating zinc, copper, chromium, nickel, cobalt, and other metals from sulfuric acid for many years. Over the past 20 years, product development efforts have improved anode performance dramatically as seen in Table I. 

Zinc electroplated onto steel gives a bright and smooth finish. It is used for decorative effect and to protect delicate objects where rough or uneven finishes cannot be tolerated (in instrument parts) and for articles that cannot withstand the pretreatment or temperatures required in the other coating processes. Electroplated zinc is also very ductile, and the process is widely... 

Zinc coatings, especially hot dip galvanizing, occupy a very important position in the automotive industry, together with electroplated zinc coatings. It is expected that in Europe, North America, and Japan the production of zinc-coated steel will approach 15 million tons, which means that per region. 

The increase in corrosion resistance is significant when applied to thin coatings, notably electroplated zinc and cadmium, and the benefits have been discussed widely. Thus Royuela (1969) reports favorable results in exposures in Spanish towns. 

Several Japanese and Korean papers deal with the problem of fingermarking of panels used in home electric appliances on chromated 20 g/m electroplated zinc, Kawanishi et al. (1992) described the use of 1 pm acrylic-silicon Kim (1992) noted a one-coat/one-bake aqueous inorganic plus organic solution Tajiri et al. (1992) cured a chromate-polyester at 210°C while Yoshimi (1992) has an intense, weldable black-dyed film (1-2 pm), but this technique has not yet been used in practice. 

Most recommendations for the heat treatment of zinc-coated steel are based on electroplated zinc-coated steel, where hydrogen is primarily picked up in the electroplating process. Even here, an unpublished report by SRAMA (Springs Research) indicates that heat treatment of zinc-coated springs is required only with steels having tensile strength greater than 1050 MPa. 

Air entrapped during encapsulation and vapor from polymeric materials such as epoxy resin can cause corrosion. The corrosive effect of vapors from plastics, rubber, and wood on zinc and cadmium has been tabulated by Knotkova-Cermakova and Vickova (1971) other work, including electroplated zinc-nickel alloys, has been discussed by Donovan and Stringer... 

International Standards Organization (1981). ISO 4520, Chromate conversion coatings on electroplated zinc and cadmium coatings, 2 pp. 

The reverse occurs during discharge of the battery as the electroplated zinc loses two electrons to the bipolar electrode and dissolves back into aqueous solution. 

Electroplated zinc is very ductile, and consequently this process is widely used for the continuous plating of strip and wire, where severe deformation may be required. 

Electroplated zinc (30 g/nf), phosphate B Electroplated zinc (70 g/m ), phosphate B Hot dip galvannealed (5-9 g/m, phosphate B Hot dip galvannealed (67 g/m ), phosphate B Electroplated zinc/nickel (18 g/m, phosphate B Electroplated zinc/nickel (44 g/m ), phosphate B Cold-rolled steel, phosphate B Cold-rolled steel, no phosphate Cold-rolled steel, phosphate A Hot dip galvanized (108 g/m ), phosphate A... 

Zinc electroplating. Zinc salt solutions are used in the electrolytic disposition of a layer of zinc on a cleaned steel surface. 

Negative Plates. The negative plates may be prepared by pasting or pressing zinc powder or zinc oxide onto a grid or by electroplating zinc from an alkaline bath to form a very active spongy zinc deposit. 

Due to concerns about the effects of lead in the environment, work is now under way to find suitable replacement materials. Zinc alloy coatings (hot dip zinc-iron or electroplated zinc-nickel) with an organic topcoat are among the most likely candidates. 

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