Electroplating solutions

When major components of plating solutions are determined, large dilutions may be required (e.g. a factor of 5000) to bring the sample into the normal working range for flame analysis. Such dilutions will, however, minimise any interference effects and viscosity effects from additives, and are thus to be preferred to the use of less sensitive lines or burner rotation. The above interference effects may be important in the determination of trace metal levels and attempts should be made to match the standards for major component levels, or to use the method of standard additions. Solvent extraction to remove the analyte from the matrix may be necessary. 

Price [67] has reviewed the application of atomic absorption to a variety of plating solutions. Iron, lead and zinc are reported as the main impurities in cyanide copper-plating baths which may contain up to 200gl 1 of copper sulphate a twenty-fold dilution of the sample for trace determination is recommended. Nickel baths may contain 60 gl 1 of nickel and it may be necessary to monitor copper, zinc, iron, lead, chromium, calcium and magnesium at the ppm level. The standard addition method is probably best for such an application. Zinc has been extracted with trioctylamine-hydrochloride when present in the range 0.03—10pgml-1 in a nickel plating solution [68]. The zinc was re-extracted back into 1M nitric acid for 

Anode coatings used in chlorine/caustic soda cells may consist of baked layers containing ruthenium and iridium on a titanium substrate. These metals have been determined by fusing the coating with potassium hydroxide/potassium nitrate [73]. The melt was dissolved in hydrochloric acid and titanium added as a buffer for ruthenium (measurement at 349.9 nm) and potassium for iridium (measurement at 285.0 nm) to overcome signal depressions in the air/acetylene flame. 

Many other household products can be analysed in similar ways to those described above for chemicals. Household bleach is essentially an inorganic chemical. There has been concern expressed about mercury levels in hypochlorite bleach because of the way it is manufactured. The cold vapour reduction/aeration method referred to above is a good way of determining low mercury levels with minimal matrix problems [82]. In the past organo-mercurial compounds have been used (e.g. as bactericides) in some household products these may be selectively determined by extraction with an organic solvent (e.g. carbon tetrachloride or benzene), and then application of the cold-vapour method following the addition of cysteine acetate, or by coupled gas chromatography/atomic absorption [83], 

---

Nickel carbonate is used in the manufacture of catalysts, in the preparation of colored glass (qv), in the manufacture of certain nickel pigments, and as a neutralizing compound in nickel electroplating solutions. It also is used in the preparation of many specialty nickel compounds. 

Cadmium, cobalt, copper, and nickel sulfamates react with lower aHphatic aldehydes. These stable compositions are suitable for use ia electroplating solutions for deposition of the respective metal (see Electroplating). 

T. Irvine, ChemicalMnalysis of Electroplating Solutions, Chemical Pubhshing Co., New York, 1970. 

Some electroplating solutions produce more uniform deposits than others, and the ability of a solution to deposit uniform coatings is measured by its throwing power (see Section 12.1). 

The sulphate bath The sulphate bath, the earliest of electroplating solutions and the simplest in composition, contains typically 150-250 g/1 of copper sulphate and 40-120 g/1 of sulphuric acid. The composition is not critical and the higher concentrations are used for plating at higher current densities, normally up to 6 A/dm. ... 

Other electroplating solutions Other solutions, which are more rarely used for plating copper, include the fluoborate bath, the amine bath, the sulphamate bath and the alkane sulphonate bath. 

Addition Agent a substance added to an electroplating solution to produce a desired change in the physical properties of the electrodeposit. 

Nickel dioxide, 77 107 Nickel double salts, 77 113 Nickel electrodes, 3 430 72 216 Nickel electroplating solutions, 9 818t Nickel extraction, 70 791 Nickel ferrite brown spinel, formula and DCMA number, 7 348t Nickel fibers, 77 108 Nickel fluoride complexes, 77 111 Nickel fluoride tetrahydrate, 77 109-110 Nickel fluoroborate, 77 111 Nickel fluoroborate hexahydrate, 4 157t, 158, 159... 

Palladium dichloride is a starting material for preparing several palladium compounds. It also is used for detection of carbon monoxide. For such detection, a paper is soaked in very dilute solution of PdCb which is decolorized by CO, methane and other reducing substances. It also is used in toning and electroplating solutions and in photography for porcelain pictures. 

Turbine blades of jet engines are coated with a protective layer of platinum aluminide to impart high temperature corrosion resistance. Platinum is electroplated onto the blade using P-salt or Q-salt electroplating solutions (28,29). The platinum is then diffusion-treated with aluminum vapor to form platinum aluminide. Standards for the inspection and maintenance of turbine blades have become more stringent. Blades are therefore being recoated several times during their lifetime. 

Chromium is used in the manufacture of stainless steel and other specialist steels, and non-ferrous alloys. Chromate salts are used as tanning agents, pigments, catalysts, corrosion inhibitors and in electroplating solutions. Although stainless steel is inert, the dissolution of chromium from this steel is likely to be the major source of chromium in food. 

Trace metals - - Reverse phase HPLC in electroplating solutions - - [313]... 

There is naturally a significant difference between the current retail price for most ionic liquids and the current cost of aqueous electroplating solutions. It is difficult to imagine that many ionic liquids will ever approach the desirable 20 / kg level. This is due fundamentally to the synthetic complexity involved in producing ionic liquids. It is, however, essential to comprehend that the cost of the liquids need not necessarily be an issue, as the key driver will be the running costs of the process, of which the capital outlay for the liquid may only be a small component. The overall cost will be made up of ... 

Experiments have been performed in which a well-characterized singlecrystal surface was immersed in electroplating solution, plated with a fraction of a monolayer to several hundred monolayers of metal, and then examined by LEED, Auger spectroscopy, and related techniques [32, 38-49]. The initial results have been very revealing and work is continuing. 

Zetrath D. Modified electroplating solution components in a low-acid electrolyte solution. US patent 20,050,077,181. 2005 Apr 14. 

Recent developments in ion chromatography are filling the analytical gap between the atomic adsorption spectroscopy and inductively coupled plasma metal spectroscopy. Ion chromatography can now not only determine what trace metals are present, but also their oxidation state, the degree of complexation, and the stability of the complex. For example, a nickel electroplating solution was analyzed by diluting it with a water eluant solution. The analysis revealed the following ion concentrations. 

Solvent effects on the Cr—O bond lengths in [Cr(ox)3]3- have been studied by XAFS spectroscopy.628 The Cr111 oxalato complexes are used in Crm-based chrome-electroplating solutions, avoiding the use of toxic and carcinogenic CrVI.114,629... 

---