Influence of Pulse Current Forward-Reverse Duty Cycle on Structure and Performance of Electroplated W–Cu Composite Coatings

Tungsten-copper (W–Cu) composites are widely used as electrical contact materials, resistance welding, electrical discharge machining (EDM), and plasma electrode materials due to their excellent arc erosion resistance, fusion welding resistance, high strength, and superior hardness. However, the traditional preparation methods pay little attention to the compactness and microstructural uniformity of W–Cu composites. Herein, W–Cu composite coatings are prepared by pulse electroplating using nano-W powder as raw material and the influence of forward-reverse duty cycle of pulse current on the structure and mechanical properties is systematically investigated. Moreover, the densification mechanism of the W–Cu composite coating is analyzed from the viewpoints of forward-pulse plating and reverse-pulse plating. At the current density (J) of 2 A/dm2, frequency (f) of 1500 Hz, forward duty cycle (df) of 40% and reverse duty cycle (dr) of 10%, the W–Cu composite coating rendered a uniform microstructure and compact structure, resulting in a hardness of 127 HV and electrical conductivity of 53.7 MS/m.

Periodic Pulse Plating of Mid-Aspect Ratio Printed Circuit Boards for Enhanced Productivity

ABSTRACT Pulse plating of copper has typically found use in the plating of very difficult, high aspect ratio printed circuit boards. Its ability to provide throwing power deep within through holes with aspect ratios as high as 30:1 is well established. This technology has long been thought of as a high technology, high cost, specialty process applicable only to high end products. This paper will discuss the advantages that pulse plating offers over conventional DC copper plating in high volume production applications for panels with aspect ratios of up to 12:1. These advantages are reduced plating time, increased throughput, and reduced plated copper thickness on the panel surface while meeting minimum in-hole copper thickness requirements.

Synthesis of Bi 2 S 3 thin films based on pulse-plating bismuth nanocrystallines and its photoelectrochemical properties

The solubility of Bi 3+ in aqueous solution is an important factor that limits the fabrication of high-quality Bi 2 S 3 thin films. In order to find a low-cost method to manufacture high-quality Bi 2 S 3 thin films, we are reporting the preparation of the Bi 2 S 3 thin films based on pulse-plating method in this paper for the first time. The nano-bismuth particles were obtained by electroplating on fluorine-doped SnO 2 (FTO)-coated conducting glass substrates with saturated bismuth potassium citrate solution as the electroplating bath, and then it was put into a muffle furnace to oxidize. Finally, the thin films depositing on FTO glass substrates were put into the thioacetamide solution for vulcanization. In the end, the Bi 2 S 3 thin films were successfully prepared on FTO glass substrates. Different characterization techniques were used to characterize the structure, morphology and photoelectrochemical properties of the prepared thin films. The test results revealed that we used this method to synthesize the high-quality Bi 2 S 3 thin films, thus the Bi 2 S 3 materials synthesized through this method are promising candidates in photoelectrochemical application.