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At present, the term of pulse plating denotes not only square-pulsed current plating but also various other types of modulated current plating.These various types of pulse plating are categorized electrically, and the gap between pulse plating theory and it's practical application are presented.And it is suggested that the research papers on pulse plating must be studied enough in proposing to bring pulse plating to the practical level.The method to choose more suitable pulse plater to it's purpose is presented, and it is mentioned that the improvement of the equipment for pulse plating including DC wiring increases the effect of pulse plating.

Amorphous alloys can be electrodeposited by direct or pulsed current. According to electrocrystallization theory, a high crystallization overpotential produces microcrystalline structure in the deposits. Thus if the amorphous phase consists of microcrystals, pulsed current is preferable for preparing amorphous alloys. However, another newly proposed theory holds that the amorphous phase structure is microcrystalline but icosahedral. This would mean that future study is needed effect of pulsed current.

The investigations show that during pulse plating with short current pulses and much longer “off” times no significant diffusion polarisation occurs during plating, so that the properties of the deposited gold-nickel alloys from an alkaline cyanide bath are largely independent of the current density. When plating is done with normal direct current under otherwise equivalent conditions the deposits show the normal dependence on the current density.

A description is given of the theoretical concepts pertaining to the electrodeposition of aluminum from alkylbenzene electrolytes. Experimental work done in static D.C. plating of aluminum and aluminum alloys is reviewed. The results obtained from experimental work done in pulse plating of aluminum alloys shows the increase in coating thickness that can be achieved by the use of this technique. Barrel plating of steel and titanium fasteners has been found to exhibit enhanced corrosion resistance following a chromatation treatment.

CuX (X=Cl ou Br) est forme durant le depot electrolytique de Cu sous courant pulse. La vitesse de corrosion du Cu pur est determine a partir de l'etude experimentale

In high-purity gold-plating baths for electronic components, a trace amount of thallium is added as a grain refiner. At high current densities, however the thallium content of the gold deposits increases and wire bondability deteriorates. In this study, pulse plating was investigated as a method of decreasing thallium content. It was found that there was little thallium in deposits obtained using pulsed waves of 125Hz frequency and a 75% duty cycle. Micrographs and X-ray diffraction patterns showed that the crystals were large and grew in a relatively random under pulse plating.

The replacement of a direct by a pulsed current in the electrodeposition of gold has a marked effect in improving the mechanical properties of the deposits and in reducing their internal stresses. For many applications in the electronics industry pulse plating therefore offers considerable advantages.

This paper shows that pulse electroplated lead can be used as well as DC plated gold as absorber material for the production of X-ray masks. This lead fulfills the demands on the absorber concerning resolution, contrast, grain size and surface roughness. Structures down to 0.3 μm were achieved, and a thickness of the lead layer of approximately 1.8 μm provides a sufficient contrast even for a 4-fold exposure dose. The mechanical stress of the pulse plated lead is negligible and no mask distortion due to the absorber stress was found, even after annealing at 100°C.

Recherche de la condition optimale densite de courant-duree de l'impulsion pour le depot simultane plomb-etain. Caracterisation microstructurale de la couche deposee par microscopie electronique a balayage. Donnees numeriques

In pulse plating the useful values of the on and off times are limited by the rate of charging and discharging, respectively, of the electrical double layer at the electrode-solution interface. The charging and discharging times are calculated as a function of the relevant parameters (pulse current density, exchange current densityi0, capacitanceC of the double layer and others). Simple, approximate relationships are also presented for the case in which no experimental values fori0 andC are available. In order to quantify the damping of the Faradaic current the concept of ‘degree of flattening’ is introduced to describe the extent of the capacitive effects. The influence of a high degree of flattening on some deposit properties is illustrated by examples.

The reduction of the thermal conductivity of low temperature co-fired ceramics (LTCC) caused by a porosification process originally developed for the local modification of the permittivity is determined by the 3ω measurement technique. Therefore, metallization lines of small width down to 20 μm are applied by galvanic pulse plating onto the roughened LTCC surface. By this deposition technology it is possible, to cover the pores without any depth penetration. Compared to the ‘as fired’ state, a reduction in thermal conductivity of up to 70% is measured independent of the LTCC type.

Pulse-plating of tin was studied in N, N-dimethylformamide baths without the presence of additives with regards to the current efficiency, the morphology of the deposits and X-ray diffraction. The tin deposits plated under the duty-cycle of 1-5% at the average current density of 10mA/cm2 exhibited a bright, smooth, fine-grained surface.

The paper outlines the application of a unique Pulsed Current technique to the Acid Copper Electrolyte used in the PCB industry. It discusses some of the inherent difficulties associated with conventional DC plating and how these pulsing techniques can overcome them to enable the production of a higher quality product despite the ever increasing demands being placed on manufacturers for better distribution and through‐hole plating.

Composite coatings have great potential due to the possibility to combine properties of two different materials in one coating. This way, new surface properties can be tailored and applied to any material's surface. Among different manufacturing routes, electrodeposition has the biggest potential in creating composite metal matrix coatings, especially nanocomposites. Nevertheless, there is a knowledge gap between the deposition of composite coatings in laboratory conditions, described in the literature, and those that are now in place on an industrial level. While micro-composites have been industrialised for about ten years, the production of Ni/SiC nanocomposite coatings by electroplating is still far from an industrial manufacturing floor. This is due to the lack of understanding of the mechanisms of nanoparticles codeposition leading to scattering results. The production of nanocomposite coatings is much more sensitive to the process parameters compared to microcomposite. The correlation between parameters and their influence on the codeposition are still not fully identified and understood. The codeposition models proposed in the literature are only valid in specific conditions, but composite depositions behave differently, or even opposite if some of the variables are modified. The main objective of this work is to identify the particle-current-electrocrystallization interactions in the production of Ni/SiC nanocomposites. A series of experiments are designed to isolate single variables and identify the controlling parameters of these interactions and their impact on the final properties. In this thesis, the effect of current density, type of current and particles size are identified as primary variables controlling the metal crystallisation and coatings properties. Among many parameters, a specific current waveform in pulse reverse mode proved to increase the codeposition rate effectively, doubling the content of nanoparticles compared to other techniques. Ultrasound assistance is also considered as stirring method when particles are suspended in the deposition bath to increase their stability and dispersion. The effect of Ultrasound on the particles codeposition and metal crystallisation is studied and compared to silent condition. Moreover, a surface treatment for the particle has been proven successful in making any particle to behave similarly in the Ni deposition bath. Furthermore, the codeposition rate doubled or tripled compared to untreated ones thanks to this treatment. Both ultrasonic agitation and surface treatment reduce the formation of aggregates, improving the particle dispersion and metal microstructure thus increasing the final hardness. The work proved the synergistic effect between particle and metal microstructure which affected the final properties of the coating. Therefore, when tailoring the composite coating to improve hardness, it is not only the amount of the particles that should be considered but also their influence on the electrocrystallisation process. Kompositbeläggning har stort potential tack vare möjligheten att kombinera två material i samma ytskikt. På detta sätt kan nya ytegenskaper skräddarsys och appliceras på ett materials yta. Elektrodeposition är den tillverkningsmetod som har störst potential att uppnå kompositbeläggningar, i synnerhet nanokompositer. Ett kunskapsgap existerar mellan elektrodeposition under laboratorieförhållanden, som beskrivet i vetenskaplig litteratur, och hur processen går till i industriell miljö. Medan industriell tillämpning av mikrokompositer pågått ungefär tio år, så har produktion av Ni/SiC nanokompositbeläggningar fortfarande inte nått fabriksgolvet. Detta är en konsekvens av bristande förståelse kring mekanismer för samdeposition av nanopartiklar som leder till varierande resultat. Produktion av nanokompositbeläggningar är mycket mer känslig för processparametrar jämfört med mikrokompositer. Korrelationer mellan parametrar och dess inverkan på samdeposition är fortfarande inte fullt identifierade och förstådda. Modeller för samdeposition som föreslås i vetenskaplig litteratur är endast giltiga under särskilda förhållanden. Kompositdeposition kan uppvisa avvikande eller till och med motsatt beteende om variabler förändras. Huvudmålet med detta arbete är att identifiera interaktioner mellan partikel, ström och elektrokristallisering under tillverkning av Ni/SiC nanokompositer. En serie av experiment är utvecklade för att isolera variabler och identifiera de parametrarna som kontrollerar dessa interaktioner och dess inverkan på ytans egenskaper. I denna avhandling identifieras strömtäthet, typ av ström, och partiklars storlek som primära variabler som kontrollerar metallkristallisering och beläggningens egenskaper. Bland många parametrar, visades en specifik vågform på strömmen i omvänd pulsläge öka samdepositionen effektivt, ledande till en fördubbling av andelen nanopartiklar jämfört med andra tekniker. Ultraljud tillämpades som metod för omrörning av depositionsbadet för förbättrad stabilitet och fördelning. Effekten av ultraljud på samdepositionen av metallkristallisering studeras och jämfört med tyst tillstånd. Dessutom har en ytbehandling för partiklarna visats framgångsrik för att få godtyckliga partiklar att bete sig likt Ni i depositionsbadet. Detta ledde till att samdepositionens takt ökade med en faktor av två till tre jämfört med obehandlade partiklar. Både ultraljud och ytbehandling av partiklarna ledde till minskad aggregation vilket förbättrade fördelningen av partiklar och metallstruktur och därigenom ökad hårdhet. Arbetet bevisar synergieffekten mellan partiklar och metallstruktur vilket påverkar beläggningens slutliga egenskaper. Vid utveckling av nya ytbeläggningar ska därför inte bara mängden partiklar beaktas utan även dess interaktion med elektrokristalliseringsprocessen.

Sur/Fin 79 — the Sixty-Sixth Annual Technical Conference of the American Electroplaters’ Society was held in Atlanta, Georgia, on June 24th to 28th, 1979, Papers dealing with various aspects of gold plating were presented and are summarized in this review.

At an International Pulse Plating Symposium held under the auspices of the American Electroplaters’ Society on April 19th and 20th, 1979, in Boston, MA., a number of papers was presented on the pulse plating of gold. The high promise for improved gold coatings prepared by this method of deposition is reflected by this review of current developments.