Why do film capacitors need to undergo the gold spraying procedure

In the production process of film capacitors, gold spraying is an extremely important process. Originally, film capacitor manufacturers generally used quaternary alloys and quinary alloys. However, due to price wars, many film capacitor manufacturers have begun to use pure zinc for gold spraying. The cost can indeed be significantly reduced. What are the disadvantages of using pure zinc for gold spraying of film capacitors?

Why do film capacitors need to undergo the gold spraying procedure?

The purpose of gold spraying is to lead out the electricity of the metal coating on the film through the gold spray paint to facilitate welding; (because the coating is thin, it cannot be directly welded, but the foil can be directly welded).

What are the gold-spraying materials for film capacitors?

Normally, quaternary alloys (tin, antimony, copper, zinc) and quinary alloys (tin, zinc, antimony, bismuth, lead) are used. Using this material, the welding performance and product high frequency DF are good, the charging and discharging performance is good, the current resistance is strong, and the life is long, but the disadvantage is also obvious, that is, the price is too expensive.

All of Safe Electronics' film capacitors are made of quaternary and quinary alloys. We promise not to use inferior pure zinc-sprayed gold.

Now many film capacitor manufacturers directly use the lowest-priced pure zinc gold spraying, which can significantly reduce costs, but the disadvantages are also obvious, that is, the gold spraying particles are rough, the capacity decays quickly, and the loss is large.If the gold-spraying particles are too coarse, it is easy to damage the film material, and the gold-spraying material is not easy to enter the end face gap, resulting in increased contact loss between it and the metallized film material.

The thickness of the gold spraying will also affect the quality of the film capacitor

In order to save costs, some film capacitors will also control the thickness of the gold spraying to save materials. However, if the gold spraying layer is too thin, the metallized film material will be damaged during welding, and the performance of the film capacitor will deteriorate.Under normal circumstances, the thickness of the gold spraying should reach 0.35MM. If the gold spraying layer is too thick, it will waste the gold spraying materials, which will also lead to increased costs and is unnecessary.