Electrolytic zinc coatings, applications

The excellent resistance of zinc to corrosion under natural conditions is largely responsible for the many and varied applications of the metal. In fact nearly half the world consumption of zinc is in the form of coatings for the prevention of corrosion of steel fabrications exposed to the atmosphere and to water. For its varied applications zinc is obtainable in a number of grades. Ordinary commercial (G.O.B.) zinc contains up to about I -5% total of lead, cadmium and iron. Electrolytic zinc has a minimum zinc content of 99-95% and contains small amounts of the same impurities. Special high-purity zinc has a minimum of 99-99% zinc. Even purer zincs are commercially available. 

Painting for corrosion protection usually involves a thorough cleaning of the metal surface to remove any corrosion products followed by application of a primer containing a corrosion inhibitor such as zinc chromate or calcium plumbate next follows a heavily pigmented undercoat for the purpose of reducing the permeation of water to the metal surface elimination of the internal circuit— the electrolyte), finally a third decorative coat that is resistant to the atmosphere. 

Industrial Heavy Duty. Application Intermittent medium- to heavy-rate discharges, low to moderate cost. The industrial heavy-duty zinc-carbon battery generally has been converted to the zinc chloride system. However, some types continue to include ammonium chloride and zinc chloride (ZnCl2) as the electrolyte and synthetic electrolytic or chemical manganese dioxide (HMD or CMD) alone or in combination with natural ore as the cathode. Its separator may be of starch paste but it is typically a paste-coated paper liner type. This grade is suitable for heavy intermittent service, industrial applications, or medium-rate continuous discharge. 

Industrial Heavy Duty. Application Low to intermediate-continuous and intermittent heavy-rate discharges low to moderate cost. This battery has generally replaced the industrial Leclanch6 heavy-duty battery. It is a true zinc-chloride cell and possesses the heavy-duty characteristics of the premium zinc chloride type. The cell electrolyte is zinc chloride however, some manufacturers may add small amounts of ammonium chloride. Natural manganese dioxide ore is used along with electrolytic manganese dioxide as the cathode. These cells use paper separators coated with cross-linked or modified starches, which enhance their stability in the electrolyte. Batteries of this formulation and design are competitive in cost to the Leclanche heavy-duty industrial batteries. They are recommended for heavy-duty applications where cost is an important consideration. This battery also exhibits a low le age characteristic. 

The device assembly was carried out by direct application of a small volume of the di-ureasUs to the surface of a glass plate onto which an indium zinc oxide (IZ0)AV03 coating had been previously deposited. The gel was dried in a vacuum oven for a period of seven days. The thickness used for each layer were 170 nm for IZO and 400 nm for WO3. The entire assembly procedure described was carried out under atmospheric condition. A second IZO-coated glass plate was placed on top of the dry electrolyte layer and the two plates were pressed together to spread the electrolyte in a thin film between the EC surfaces. The entire assembly procedure described was carried out under atmospheric conditions. 

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