Editing Electroplating (section)

===Pulse electroplating===
{{See also|Pulse electrolysis}}
The pulse electroplating or pulse electrodeposition (PED) process involves the swift alternating of the [[electrical potential]] or [[Electric current|current]] between two different values, resulting in a series of pulses of equal amplitude, duration, and polarity, separated by zero current. By changing the pulse amplitude and width, it is possible to change the deposited film's composition and thickness.<ref>{{cite journal|last1=kunji durai|first1=M. S.|first2=Mathy|last2=chaala|title=Pulse and pulse reverse plating—Conceptual, advantages and applications|journal=Electrochimica Acta|volume=53|issue=8|year=2008|pages=3313–3322|doi=10.1016/j.electacta.2007.11.054}}</ref>

The experimental parameters of pulse electroplating usually consist of peak current/potential, duty cycle, frequency, and effective current/potential. Peak current/potential is the maximum setting of electroplating current or potential. Duty cycle is the effective portion of time in a certain electroplating period with the current or potential applied. The effective current/potential is calculated by multiplying the duty cycle and peak value of the current or potential. Pulse electroplating could help to improve the quality of electroplated film and release the internal stress built up during fast deposition. A combination of the short duty cycle and high frequency could decrease surface cracks. However, in order to maintain the constant effective current or potential, a high-performance power supply may be required to provide high current/potential and a fast switch. Another common problem of pulse electroplating is that the anode material could get plated and contaminated during the reverse electroplating, especially for a high-cost, inert electrode such as [[platinum]].

Other factors that affect the pulse electroplating include temperature, anode-to-cathode gap, and stirring. Sometimes, pulse electroplating can be performed in a heated electroplating bath to increase the deposition rate, since the rate of most chemical reactions increases exponentially with temperature per the [[Arrhenius equation|Arrhenius law]]. The anode-to-cathode gap is related to the current distribution between anode and cathode. A small gap-to-sample-area ratio may cause uneven distribution of current and affect the surface topology of the plated sample. Stirring may increase the transfer/diffusion rate of metal ions from the bulk solution to the electrode surface. The ideal stirring setting varies for different metal electroplating processes.