To increase the conductivity of PCBs, gold plating is used to cover the other metals on the board with gold. Gold plating, the most prevalent method of the gold deposit onto a PCB, is also one of the simplest.
To achieve the desired effect, a high concentration of gold ions gets formulated in the plating solution. Ionic gold is simply a gold atom that lacks an electron by applying the gold solution to a cathode. A surface contains positive charge atoms, the latter form chemical bonds with the former.
With this method, the gold layer on the substrate getting coated is less than fifteen-millionths of an inch thick, which is extremely thin.
Why is Gold Plating Used on PCBs?
The following factors contribute to the widespread adoption of gold for PCBs:
· Efficient Electrical Conduction
Its strong conductivity is crucial for printed circuit board uses.
· Avoids corrosion
Even copper and silver have strong conductivity. Their susceptibility to corrosion reduces their useful life. Gold is resistant to oxidation and corrosion. And it can also get used to safeguard underlying metals.
· High heat resistance
A strong tolerance for heat lowers the risk of fire.
· Reusable
In a melting pot, gold may be easily recovered.
· Flexible
It can get shaped to fit a variety of uses, and even the thinnest layers provide effective results.
Difference Between Immersion Gold Plating & Gold Plating
PCB gold plating and immersion gold both involve applying a thin layer of gold to the surface. But there are important differences between the two.
Both procedures use different chemical reactions, which accounts for the noticeable hue difference between them. Submerging the boards in a solution of gold salts produces the same effect as gold plating, which is the binding of gold atoms to the surface of the metal by electron displacement.
When these processes collide, different crystal formations are produced. This distinction manifests itself in the extreme hardness of gold plating compared to the pliability of immersion gold as far as durability and solderability go. There’s a huge difference between how hard and how soft something is.
Soldering-required gold fingers or areas on a printed circuit board (PCB) may benefit from either gold immersion or gold plating, depending on the specifics of the application. One must be familiar with the pros and cons of both methods. As well as the appropriate contexts in which they can get applied.
Why Use Gold Plating Board?
Gold plating is usable over immersion gold for PCBs because it is more durable. Electronic components that come into frequent contact with one another benefit greatly from getting made of hard gold. The gold fingers on a PCB, which are used to link the PCB to another board, are one such area where gold plating is increasingly widely used.
Some gold fingers should be able to endure the abrasion that results from imperfect or repeated insertion since they are removable and inserted from another electronic board many times over the course of a PCB’s lifetime. The durability of gold fingers with gold plating is superior to that of immersion gold fingers in this scenario.
Additionally, the ease of gold plating may make it a more appealing option. Gold plating can get used in place of gold immersion if the manufacturer does not possess the necessary equipment. In addition, the PCB can get brushed with the solution of gold plating instead of submerged if only a small section needs to get plated.
Gold plating has the disadvantage of being more expensive. Because a thick gold layer is necessary, soldering the PCB will be impossible if the material is too thick. However, many producers may find that the benefits of using hard gold for touch and slide contacts outweigh the material’s higher cost.
Why Use Immersion Gold PCBs?
Immersion gold has a lot of benefits. Immersion gold is preferred over gold plating for soldering by many. Because it is softer and thus requires less heat to melt the solder. The extra convenience of using immersion gold implies fewer customer complaints about the welding quality, and it may also cut down on time it takes to solder the PCB.
When it comes to electroless nickel gold finishes, gold immersion is typically the preferred method. The goal is to prevent the nickel layer from oxidizing by forming a protective barrier around it. However, during the soldering process, the gold is absorbed by the solder. This process leaves behind a permanent bond between the solder and nickel.
Immersion gold produces a smoother surface than gold plating because it deposits a thin coating of gold by dislodging the atoms on the surface. Rather than attaching them on top of them. If the printed board needs to be perfectly flat. This capability can help, and it could be useful when performing any other kind of work on the board.
Immersion gold is pliable, making it simple to exert controlled pressure. The fact because immersion gold is indeed not as brittle. And hence less prone to fracture under strain contributes to its durability and makes it easier to solder.
Immersion gold is a crucial step in the PCB manufacturing process since it gives the manufacturer greater leeway and results in a more uniform end product. Because of this uniformity, immersion gold seems to be more likely to provide the desired coverage. It aids in quality control and sets reasonable expectations for personnel handling the PCBs.
Amazing 6 Benefits of using Gold Plating PCBs
Printed circuit boards typically employ a gold plating kit. Gold’s high conductivity, exceptional oxidation resistance, and extended life make it an excellent choice for PCB surface treatments. A thin gold layer is deposited onto another metal using electrochemical or chemical plating to create a gold plating. The thickness of this gold coating is normally between 0.25 and 5 microns (0.00001 to 0.0002 inch). The gold isn’t electroplated directly onto the copper surface of the PCB. The gold plating process begins with an electroplating layer of nickel. The durability of the PCB is enhanced by the strong bond between the layer and the PCB.
Using a gold finish on your printed circuit board (PCB) has a number of advantages.
You may easily and successfully re-plate several locations on a component or PCB using the Gold Re-plating Kit from BEST. Hands-on instruction in re-plating gold on PCB fingers, parts, and other parts is available from BEST.
1. Corrosion Resistance
The chemical reactivity of gold is very low. It has a longer shelf life than copper or silver because it does not interact with oxygen. When it comes to protecting against corrosion, gold is extremely reliable. In both natural and man-made settings, it poses no danger. Gold-plated components last longer and need to be changed less often. This means its useful life is greatly extended.
2. Conductivity
The electronic industry relies heavily on gold because of its high conductivity and durability as a contact metal. It has excellent thermal and electrical conductivity. At 20 °C, the electrical resistivity of gold is 0.022 micro-ohm m. At the same time, its thermal conduction is 310 W m-1 K-1. It’s a perfect conductor because it doesn’t lose its properties in different conditions. Surface oxides are not formed due to gold’s anti-oxidation characteristics. Gold’s shiny sheen makes for a sturdy bond between mating surfaces.
3. Durability
Gold has high durability and stands up well for everyday use. Spreading rather than depleting, this metal is extremely long-lasting.
4. Protection Against Heat
As its melting point is 1947 degrees Fahrenheit, gold is a very high-temperature metal. Therefore, it retains its functionality even when heated to very high temperatures. For electronics that are frequently subjected to high temperatures, gold provides better protection against malfunctions caused by heat.
5. Coating Application Simplicity
Making sure that a thin layer of metal is electroplated onto electrical connections is essential. Coatings that are too heavy may hinder the functionality of the item. Due to gold’s malleability, it is simple to produce a very thin layer for the application. The prices can be drastically decreased by applying a thin gold layer coating.
6. No Fretting Degradation
We did not observe any fretting corrosion, which is the breakdown of material at the interface between two mating surfaces. In corrosive environments, they may experience slight oscillations. Gold cannot be fretted because of its hardness. There will be no wear and tear from rubbing or friction over time.
Conclusion
Incorporating gold into your PCBs is a great way to boost the conductivity of their individual components. Reduced current loss and reduced temperature on the circuit board are two benefits.
There are pros and cons to using either immersion gold or gold plating to finish your PCB. When it comes to coatings, gold plating results in a harder, flatter layer, while immersion soft gold results in a softer, more uniform coating.
Each has its own unique strengths and weaknesses, and you should employ them accordingly. For instance, the best way to make gold fingers that can resist the abrasion of removal and insertion is to have them gold-plated. However, soldering, which calls for both uniformity and pliability, is best done with immersion gold. Both methods are crucial in the manufacture of reliable printed circuit boards.
