Plate parting

Process Details. Automated processing lines aHow low cost production of plated parts. Rejects, which are typicaHy less than 5% of production, can be stripped and replated, or reground and remolded. The cost of chemicals is typicaHy 1.07—2.15/m. ... 

Corrosion Resistance. The environment to which a plated part is to be exposed should be a part of any definition of corrosion resistance. Problems arise in testing a part in its intended environment in part because of the long time period required. In many plating processes, corrosion resistance is direcdy proportional to the plate thickness, so a specification on plate thickness is a much faster method of indirectiy measuring corrosion resistance. In specifying a corrosion resistance requirement for the production of plated goods, accelerated tests are used especially if plate thicknesses caimot be related to corrosion protection. 

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). 

Ductility Tests. The ductihty of plated metals differs considerably from the corresponding thermally cast metals. Additionally, ductihty which is an important property if parts are to be deformed after plating, varies with the chemical composition of the plating solution, as well as the operating conditions of a given plating process. Ductihty can also be important when plated parts are stressed in use. Some metal deposits have coefficients of... 

Barrel plating of parts in copper cyanide solutions utilizes various formulations, some weaker, some stronger than the high speed baths. When plating parts that tend to stick together or nest during the barrel rotation, the free cyanide may need to be increased. This may require 35—40 g/L free potassium cyanide or more with an equal copper content. 

For the torque coefficient, K, reported values range from 0.153 to 0.328 for cadmium plated parts, with a mean of 0.24 (Shigley and Mischke, 1996). Therefore, applying the same reasoning as above ... 

Particular fabrication requirements, including the need to assemble or plate parts. 

Port (o) = 13 Total Plates Port (b) = 11 Total Plates Part (c) = 8.5 Total Plates... 

Fig. 1.48 Examples of differential aeration cells (a) and (b) Differential aeration cells formed by the geometry of a drop of NaCl solution on a steel surface (c) differential aeration cells formed by the geometry of a vertical steel plate partly immersed in a NaCl solution. Increasing concentrations of Na2 CO3 decrease the anodic area (d) until at a sufficient concentration attack is confined to the water line (e) (/) shows the membrane of corrosion products formed at water...

Supplemental films The Batelle Memorial Institute has developed a post-treatment for nickel plus chromium coatings in which the plated part is made cathodic in a solution containing dichromate. A film thereby formed on the surface seals pores in the coating through which corrosion of the nickel might otherwise occur. Later work suggests, however, that micro-cracked chromium gives superior results. 

It has been shown that chromium is virtually unattacked by the CASS test solution Nickel, on the other hand, is corroded at a substantial rate (about 0-072mm/y), the presence of the copper ions tending to maintain the nickel in an active state . Thus, in the CASS test (and in the Corrodkote test as well) accelerated galvanic corrosion of the nickel occurs at any discontinuities in the chromium layer. Good correlation between the results of the CASS test and the performance of plated parts in service has been reported . 

Stanley, P. E. (1992). A survey of more than 90 commercially available luminometers and imaging devices for low-light measurements of chemiluminescence and bioluminescence, including instruments for manual, automatic and specialized operation, for HPLC, LC, GLC and microtiter plates. Part I descriptions. T. Biolumin. Chemilumin. 7 77-108. 

Mandich, N.V., Important practical considerations in chromium plating—Part IV, Met. Finish., 97, 9, 1999. 

Composite processing can obtain nearly all part shapes including plane or warped surfaces profiles hollow parts bulky parts sheets, slabs and plates parts with inserts, etc. 

A. Lozano, L. Valino, R Barreras, and R. Mustata. Fluid dynamics performance of different bipolar plates. Part II. Flow through the diffusion layer. Journal of Power Sources 179 (2008) 711-722. 

The work on surface coatings was carried out on mild steel panels to BS1449, Steel Plate, Part IB, CR3/FF and aluminium, 99.9% pure to BS1470, Grade SIC-H8. The adhesive test specimens consisted of flat headed bolts, 12.5 mm diameter, manufactured from mild steel round bar stock to BS970 Part I, stainless steel round bar stock to BS970 Part 1, 1/431/S29 and aluminium 99.9% pure. 

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