Electrodeposition of alloys XIX: Electrodeposition of lead-tin alloys

Pb-Sn alloys containing from 1.2 to 94.3 wt.% Sn were electrodeposited from aqueous solutions prepared from diethylenetriaminepentaacetates of the two metals. The effects of current density and the solution composition on the composition of deposits and cathodic current efficiencies were investigated. Pb-Sn alloy deposition was of irregular type. At current densities equal to or less than 2.0 A dm^-2, lead deposited preferentially. At current densities of more than 2.0 A dm^-2 and in solutions containing more than 50.0 met.% Sn (the percentage weight of the total metal content), preferential deposition of tin occured. An increased in the tin content of the bath increased the percentage of tin in the deposit. The presence of chloride ions in the bath did not seem to affect the composition of the deposit.     

Electrodeposition of Ruthenium

A new electrolyte has been developed for the electrodeposition of ruthenium. Deposits are bright at cathode current efficiencies up to 100%, the bath is stable in operation and has a useful working life, expressed as total deposit weight, of over 50 g ruthenium per litre of electrolyte. The process is based on a novel,? readily prepared anionic complex of ruthenium having the formula (NH₄)₂ [Ru₂NCl₈(H₂O)₂].     

Electrodeposition of alloys XVIII: Electrodeposition of Bi-Sn alloys and their structure

A new Bi-Sn plating bath has been developed from which alloy deposits over a wide range of compositions can be obtained by varying the solution composition and plating conditions. The alloy deposition was of the anomalous type and bismuth behaved as the less noble metal. Bright alloy deposits were obtained under certain conditions. Increase in current density, pH and temperature increased the bismuth content of the alloy plate. The phenomena of inversion pH and temperature were observed in this system. The X-ray structure of the deposits is reported.     

The Electrodeposition of Rhodium

As part of a continuing effort to improve the durability of decorative plated automobile parts, a deleterious type of chromium cracking and the changes in the microstructure of nickel brought about by addition of a sulphur-containing additive have been studied. Type Y cracking of 0·02–0·05 mil chromium deposits was found to result from interaction of the internal stress of the deposit with tensile stress induced by directional abrasion of the nickel substrate. A similar type of cracking was found to occur in a bright nickel plus chromium plate on directionally abraded steel. Reduction of the stress by annealing or removal of the stress layer by electropolishing eliminated this type of cracking. The size of the columnar structure of a Watts deposit was found to decrease when sodium allyl sulphonate was added to the bath. With increasing concentration, the columns gradually disappeared leaving visible only a laminar structure. The transition from columnar to laminar structure occurred well below the normally used additive concentration. In a fully bright deposit, perpendicular faults associated with scratches in the basis metal were observed. These were duplicated in deposits on electro-formed precision roughness standards. The effects of these phenomena on corrosion of decorative plated coatings are discussed.     

The Electrodeposition Exhibition

This paper is intended for guidance to the practical plater for preventing and curing the most commonly encountered troubles in plating solutions. It is not intended to be exhaustive, nor is it written from an academic point of view. The remedies given are those which a practical man with the usual facilities of a plating shop at his disposal can reasonably be expected to employ. Laboratory methods are seldom applicable on a large scale. The following types of solutions are dealt with:

Brass; Cadmium (Cyanide); Chromium; Copper (Acid and Cyanide); Lead (Fluoborate and Sulphamate); Nickel (Watts type and Bright Nickel); Silver; Tin (Sodium Stannate); and Zinc (Cyanide).

In all cases symptoms of troubles and remedies are given on the assumption that the particular type of solution trouble has actually been confirmed and all other possible causes been eliminated. The value of routine analysis of plating solutions as a preventive to serious troubles and resulting loss of production cannot be overrated. Haphazard methods and “rule of thumb” should by now be extinct in the workshop.     

The Electrodeposition of Iron-Zinc Alloys

Methods are given for depositing iron-zinc alloys of 3 to 90% zinc content from sulphate baths and attention is drawn to the useful properties of these deposits. Under a given set of plating conditions the iron-zinc ratio in the deposit is directly proportional to that in the bath. Lowering either the current density or the pH raises the zinc content of the deposit. Some baths have a levelling action, since bright deposits can be prepared from them on an etched surface. Examples of such baths are: (i) FeSO₄-7H₂O 248, ZnSO₄-7H₂O 8·8, (NHJ₄)₂SO₄ 118, KCl 10, citric acid 0·5 g./l., operated at pH 1·7, 50°G, 200 amps./ft.² and giving a 6% zinc alloy of 560 D.P.N, hardness;

(ii) FeSO₄-7H₂O 174, ZnSO₄-7H₂O 88, (NH₄)₂ SO₄ 118, KCl 10, citric acid 0·5 g., Teepol 0·4 ml./l., operated at pH 1·7, 50°C, 180 amps./ft.² and giving a 60% zinc alloy of 350 D.P.N, hardness.

The throwing power of the baths is comparable with that of a bright nickel bath. Pitting can be overcome by using a wetting agent (Teepol or Lubrol W) and operating at high temperature (80° C.) and low pH (<1·8). Under these conditions the deposits are usually matt and light grey in colour.

Alloys with zinc contents >ca. 30% have electrode potentials in N/10 KCl nearly equal to that of pure zinc. In the C.R.L. beaker test, the alloys with zinc contents between 30 and 90% are, in general, more corrosion resistant than pure zinc. Various applications of these alloys are proposed, including their use as an undercoat for paints and chromium plating and for decorative finishes indoors.

Deposition of iron-zinc alloys from chloride baths is dealt with briefly. A matt, corrosion-resistant alloy of 60% zinc content can be obtained, at pH 1·8, 50° C., and 50 amps./ft.², from a vigorously stirred bath of the following composition:—FeCl₂·4H₂O 177, ZnCl₂ 42, NH₄Cl 100, KCl 15, citric acid 0·5 g./l.

A colorimetrie method for the analysis of zinc in the presence of iron is described.     

Functional Composite Zinc Electrodeposition

The paper presents research into composite deposition with a electrolytic zinc matrix and inert particles.

This type of plating was studied in order to obtain superior functional performances over traditional zinc electrodepositions, such as higher hardness, wear and friction resistance and better corrosion resistance.

The study comprised: establishment of electrolyte composition; disperse phase behaviour on grain structure; effect of current density and electrolyte dynamic regime on co-deposition; plating characteristics.     

The Electrodeposition of Porous Metal

An account is given of the production of coherent porous electro-deposits of copper, nickel and zinc by the use of Aquadag colloidal graphite as an addition agent. Coherent deposits of at least 50% porosity have been produced.     

电铸技术的发展及应用

通过阐述电铸的基本原理，分析了电源、电解液和阳极材料等电铸要素对电铸技术发展的影响，并结合电铸的自身优点介绍了电铸技术的应用情况，在正确面对并处理好电铸技术存在的不足的情况下，电铸作为一门交叉学科的技术仍具有广阔的发展空间和应用前景。     

The Electrodeposition of Sheet Chromium

The brief survey of the author's experience in barrel enamelling small parts that is given here is followed by some details on the factors that are involved in the process. It is emphasised that no rules can be formulated for obtaining satisfactory results with a given load : an empirical approach is necessary in each case, and one of the difficulties that faces the finisher is the lack of scrap parts for this purpose. However, when a suitable combination of paint formulation, load and process time is arrived at, barrel enamelling does afford a very economical way of treating large quantities of small parts.     

Electrodeposition of Ni-SiC nanocomposite film

The point of zero charge(PZC) of SiC nanoparticles was determined by means of standard potentiometric titration method, while the influences of the main technological parameters on the microstructure of electrodeposited Ni-SiC composite film were studied and optimized. The results show that high bath pH value favors SiC nanoparticles negatively charged and high bath temperature promotes them positively charged. Under the experimental conditions, sodium dodecyl-glycol is proven to be an effective surface modification anionic surfactant for SiC nanoparticles. The results also show that the optimized Ni-SiC composite film is composed of the nanoparticles with the average grain size in the nanometer range (100 nm), and SiC nanoparticles disperse into the nickel matrix uniformly.     

进油嘴皮圈橡胶模具设计

介绍了进油嘴皮圈模具结构的设计和改进过程,同时说明了模具设计中应注意的一些问题。     

电沉积纳米晶合金的最新进展

用电沉积法制备纳米合金是近期研究及发展起来的新技术.综述和讨论了过去10年来电沉积纳米合金的制取方法、特性和应用.目前,电沉积纳米合金技术已经从实验室研究发展成为经济实用的纳米材料工艺.由于纳米合金具有很多优异的性能,包括高的硬度、耐磨性、耐蚀性、电磁性、光学性及抗高温氧化性等,并初步应用于生产,已受到人们的极大关注.     

Electrodeposition of Tin For Refrigerating Purposes

Results are presented of experiments on Chromate films on zinc, produced by dipping in sodium dichromate solutions of the type used in the Cronak process and variations thereon. The work covered the effect of solution composition, time of immersion, etc., on the films produced and their characteristics, in particular the protective value under humid corrosion conditions. Preferred conditions for carrying out the filming process are described.