Zinc plating

Both -hydroxybenzaldehyde and its methyl ether, -methoxybenzaldehyde [123-11-5] (p-anisaldehyde) have found extensive use in electroplating. The most widespread appHcation has been in alkaline bright zinc plating, both in non-cyanide (77) and in cyanide-containing (78) baths. The aldehydes act as both brightening and leveling agents. 

MSA Zinc Plating Process, Technical Bulletin, Elf Atochem North America, Philadelphia, Pa. 

The reproducibility of test results between labs using the neutral salt spray tests has not been consistent, but the repeatability, within one lab, is better, and the test has value in comparing variations in coating systems. Correlation of hours of exposure in the salt spray test to actual performance of the plated part in service, even in marine atmospheres, is not consistent and usually avoided. A classic example is that cadmium deposits outlast zinc deposits on steel in salt spray tests and clean marine atmospheres, yet zinc outlasts cadmium when exposed to real, industrial atmospheres, because of the presence of sulfur-bearing corrodents in industrial environments. An important variable in salt spray testing is the position of the surface to be tested. Whereas the surface of test panels is specified to be 15—30° from the vertical (40), when salt spray testing chromated zinc-plated specimens, this range has appeared excessive (41). 

The torque values listed in Table 4-153 apply to casing with zinc-plated... 

This type of corrosion can take place on any new surface of zinc and is best prevented by storing the metal in a dry, airy place until a protective layer has been formed. Zinc which has been properly aged in this way is safe against white-rust formation. Various methods are employed to prevent white rust. A chromate treatment is widely used for zinc-plated articles and for galvanised sheet, and occasionally for zinc die castings. Fatty substances, such as oils or lanolin, are sometimes used to protect larger items. 

The standard of cleanliness which must be achieved has been stated to be that which will allow the subsequent process to be carried out satisfactorily . As an example, the degree of cleanliness required to satisfactorily zinc plate from an acid solution is somewhat higher than that required prior to zinc plate from a high-cyanide alkali zinc solution. This should never be taken as a licence to skimp on surface preparation. However, the arguments over surface-tolerant paint coatings abound and will probably continue. It is to a very large extent true that problems of early failure in metal finishing are traceable to incorrect or insufficient surface preparation. 

Zinc plating Cadmium plating 25-50 56-112 40-80 32 (optimum) 1-2 (vat) 0-3-0-7 (barrel)... 

Typical thickness of coating on galvanised sheet or sherardised componenis. Typical thickness of zinc plating. 

Paint applied to a suitably prepared zinc coating will last longer than would be the case if it were applied direct to iron or steel, and the need for repainting thus becomes less frequent. With hot-dip galvanised or zinc-plated coatings, however, it is necessary either to use special primers or to prepare the surface before painting. This is primarily because most oil-based paints react with the unprepared zinc surface to form zinc soaps resulting in poor adhesion. 

Technical Notes on Zinc. Separate leaflets entitled Zinc Coalings, Galvanising, Zinc Spraying, Sherardising, Zinc Plating and Zinc Dust are available from Zinc E>evelopment Association, London... 

Aes, H. W., Handbuch der Galvanotechnik Carl Hanser Verlag, Munich, Chapter 17.06, Zinc (plating) (1966). (Typescript translation from German, in Z.D.A. library)... 

Practical details of the Cronak process are given in Specification DEF-130, and a comprehensive account of the process as applied to zinc plate has been published by Clarke and Andrew. Fig. 15.5 shows the loss of zinc and the... 

We consider oxidation first. To show the removal of electrons from a species that is being oxidized in a redox reaction, we write the chemical equation for an oxidation half-reaction. A half-reaction is the oxidation or reduction part of the reaction considered alone. For example, one battery that Volta built used silver and zinc plates to carry out the reaction... 

Between 1962 and 1982, pennies were made of brass, which is an alloy composed of 95% copper and 5% zinc. In 1982, the rising price of copper led to a change in the composition of the penny. Beginning in 1982, pennies have been made of zinc plated with copper. These pennies contain 2.5% copper and 97.5% zinc. In this experiment, the two different types of pennies will represent two isotopes of an element. 

FSM Sosnowiec manufactures automobile lamps, door locks, and window winders for the Polish-manufactured Fiat cars. The lamp bodies are made of zinc-aluminum alloy and then copper-nickel-chromium plated. The door locks and window winders are made of steel and then zinc plated. The wastestreams contain cyanide and the heavy metals chromium (VI), copper, zinc, and nickel. The company carries out the traditional treatments of detoxification, neutralization, and dewatering.29... 

Zinc plating is still effective against rust. 

Accidental contamination of a metal scoop with flake sodium hydroxide, prior to its use with zinc dust, caused ignition of the latter [1]. A stiff paste prepared from zinc dust and 10% sodium hydroxide solution attains a temperature above 100°C after exposure to air for 15 min [2], The residue of zinc dust and sodium hydroxide solution from a lecture demonstration involving zinc plating a copper coin presents a high fire risk if discarded onto paper in a waste bin, ignition of the paper having occurred on many occasions. Dissolve the residue in dilute acid before flushing away with water [3],... 

Newt, Triturus cristatus, adults, held in tank with a zinc-plated base South African clawed frog, Xenopus laevis 200 to 3000 overa 7-day period Zinc-poisoned newts were lethargic, ate poorly, and had skin darkening prior to death. Zinc residues were elevated in kidney, brain, liver, and intestine, when compared to controls. The hippocampus region of the brain of poisoned newts contained zinc-rich cells 82... 

Acid chlorides, 10 485 23 649 Acid chloride zinc plating, 9 828t Acid cleaners, ethylene oxide polymers in, 10 689... 

On Reproduceability from the Photopolymer Plate to Paper-Mold The images in a negative film can be reproduced with good fidelity. Presently used zinc plates, because of their suspected low color loss, show a less fidelity compared with photopolymer plates, but their reproduceability are very similar as shown in Table 2. 

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