Electrodeposited coatings

Brinell Tests of Steel Products Comparison Hardness Tester Practice Rockwell Test on Cemented Carbides Rockwell Test for Sintered Materials Knoop Test for Electrodeposited Coatings Webster Hardness Gauge Barcol Test of Aluminum Alloys... 

Nonferrous Metals-, Electrodeposition Coatings-, Metal Powders-, Surgical Implants, Part 7, 1972 Annual Book ofASTM Standards, American Society for Testing Materials, Philadelphia, Pa., 1972. 

A.STM B456, Std. Spec, for Electrodeposited Coatings of Copper Plus Nickel Plus Chromium and Nickel Plus Chromium, American Society for Testing and Materials, Philadelphia, Pa., 1993. 

In addition to the alloys in Table 4.21, Ni-Sn and Ni-Ti alloys also possess useful corrosion resistance. Ni-Sn alloys are extremely brittle and, because of this, are used only as electrodeposited coatings. Ni-Ti alloys over a wide range of compositions have been studied, of which perhaps the intermetallic compound NiTi (55 06Ni-44-94Ti) has attracted the most interest. 

An electrodeposited coating is never, in practice, completely uniform in thickness. The actual thickness of metal deposited at a particular point in a given time is dependent on the current density (i.e. the current per unit area) at that point, and the current density is not uniform over the whole surface... 

It will be seen that the design of articles to be electroplated can have a considerable effect on the corrosion resistance of the electrodeposited coating. The chief effects are the result of variations in deposit thickness, but also important are features which can influence the adhesion, porosity and physical properties of the deposit. Good design will also avoid features of the plated article capable of trapping liquids or solid contaminants which might cause more rapid corrosion. 

The hot-dipped coatings are distinct from the others in having practical thickness limits and in possessing an inner layer of intermetallic compound, usually described as the alloy layer. The flow-melted electrodeposited coatings also have an alloy layer, which is somewhat thinner than that obtained in hot dipping. 

Tin coatings are ductile and are able to contribute a lubricating effect in the deep drawing of steel. The presence of the thin alloy layer in flow-melted tinplate coatings does not impair this property appreciably but bright electrodeposited coatings may be less ductile than others. 

With tin coatings on brass, the interdiffusion of coating and substrate brings zinc to the surface of the tin the action can be rapid even with electrodeposited coatings. The effect of zinc in the surface layers is to reduce the resistance of the coating to dulling in humid atmospheres, and the layer of zinc corrosion product formed makes soldering more difficult. An intermediate layer of copper or nickel between brass and tin restrains this interdiffusion . 

Other aspects of engineering electrodeposited coatings A great deal of information has been published on important, but specialised, aspects of engineering nickel coatings. 

The mono- and disubstituted organotins considered here are used as stabilizers in PVC or as catalysts for the production of electrodeposited coatings (mainly in motor vehicle primers), sihcone rubbers, esterification and powder coatings, and polyurethanes, as well as for coating glass. 

Phosphate coatings are formed in the metal surface, incorporating metal ions dissolved from the surface. This creates a coating that is integrally bonded to the base metal. In this respect, phosphate coatings differ from electrodeposited coatings, which are superimposed on the metal. Most metal... 

Anodic electrodeposition (AED), 10 448 Anodic electrodeposition coatings, 10 381 Anodic inhibitors, 7 815 Anodic oxidation, on tantalum, 24 327—330 Anodic oxidation waste treatment, 9 643 Anodic oxide films... 

Cathodic electrodeposition coatings, 10 410 Cathodic inhibitors, 7 815 Cathodic protection, 7 804-806 Cathodic stripping voltammetry, 9 569 Cathodoluminescence microscopy, 16 484 Catholyte systems, 9 675-676... 

The main fields of application are in mirror coatings [5.77], [5.125], electrodeposition coatings, and primers (see Table 39). 

Many of the finishes applied to other types of metal products can also be applied to zinc die castings, although some differences in formulation as well as occasional differences in method of application may be desirable. The types of finishes applicable to zinc die castings include mechanical finishes (buffed, polished, brushed, and tumbled) electrodeposited finishes (copper, nickel, chromium, brass, silver, and black nickel) chemical finishes (chromale, phosphate, molybdate and black nickel) and organic finishes (enamel, lacquer, paint and varnish, and plastic finishes). Electrodeposited coatings of virtually any metal capable of electrodeposition can be applied to zinc die castings. 

ISO 2179, Electrodeposited Coatings of Tin—Nickel Alloy, Specification and Test Methods, ISO, Geneva, Switzerland, 1986. 

Platinized platinum — Metallic platinum covered with a rough large-surface-area platinum coating. The very well-developed metal surface results in a Pt -> electrode of a large true area that is relatively nonpolar-izable. A platinized platinum electrode can be obtained by cathodic -> electrodeposition of a rough Pt deposit at Pt-metal electrode from a solution consisting of chloro-platinic acid (3%), lead acetate (0.025%), and hydrochloric acid (ca. 1%) The name of this electrodeposited coating -r platinum black comes from deep black color and dull surface of the deposit. In fact, the dark black color appears when lead is used as an additive. When pure... 

This pigment is said to be bifunctional. It combines corrosion protection and light scattering in a single pigment [5.95]. It is recommended for application in water-and solvent-borne primers as well as in cathodic electrodeposition coatings and coil coatings [5.95]. The typical properties of this anticorrosive are summarized in Table 5.12. 

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