FI-7885 is an immersion gold bath — chemical gilding, in the language of the trade — that deposits a dense gold layer onto nickel and nickel-alloy surfaces. It works by displacement rather than electrolysis: no rectifier, no anodes, and no current density to calculate across a panel of mixed pad sizes. Gold ions in the bath exchange with nickel at the surface, and the reaction slows to a stop on its own once that surface is covered.
Board shops run it as the last step of a nickel gold plating sequence. Electroless nickel builds the barrier over the copper, and the gold seals that barrier so the pad is still solderable when it reaches the assembly line. Because the deposit is thin and follows the shape of the nickel beneath it, the pad stays flat.
The layer underneath does most of the work. Adhesion, colour and solderability all depend on the electroless nickel plating being sound — right phosphorus level, properly activated, rinsed clean before the part reaches the gold tank. This bath cannot rescue a passive or contaminated nickel surface, and it is not designed to try.
Fengfan supplies it alongside the rest of a working line: zinc and zinc-nickel brighteners, acid copper, electroless nickel, tin processes, passivation and anodizing chemistry. A shop running several finishes deals with one supplier across the whole industrial metal plating sequence instead of a different vendor for every tank.
| Product type | Immersion (chemical) gold process |
| Gold metal content (Au) | 0.5–2.5 g/L |
| Gold concentrate addition | 50–125 ml/L |
| pH | 4.0–5.0 |
| Operating temperature | 80–90 °C |
| Immersion time | 10–15 min |
| Deposit thickness | up to 0.2 µm |
| Deposit colour | 24 carat gold |
| Substrate | Nickel and nickel alloys |
| Typical applications | PCB nickel-gold finishing; decorative work |
A PCB pad is a stack: copper, a nickel barrier, then gold. The nickel gold plating step is the surface the assembly house actually works with, so it has to do two jobs at once — wet with ordinary solder, and survive storage without oxidising before the board is built.
On most boards the barrier is a mid or high phosphorus electroless nickel plating layer, and the gold only exchanges where that nickel is clean and active. Nickel thickness, phosphorus level and the transfer time between the nickel tank and the gold tank all show up in the final result; a properly built barrier gives an even colour and a solder joint that forms the first time.
The gold sits at the end of the metal plating process, after the nickel and before inspection and packing. A defect that started three tanks earlier surfaces here, and nothing downstream will correct it — which is why the pre-treatment and the nickel bath deserve as much attention as the gold itself.
Avionics boards are built in small batches, qualified once and then expected to behave identically for a decade. That puts the emphasis on repeatability rather than throughput: the electroless nickel plating underneath has to be consistent from lot to lot, and the gold on top has to seal it the same way every time. An immersion bath suits that pattern — the deposit depends on temperature, time, pH and gold concentration, all of which are measurable and easy to log, rather than on current distribution across a geometry that changes with every build.
Avionics is a small corner of industrial metal plating, but the requirements it sets are the ones every serious board shop recognises: a stable deposit, solderability that does not drift, and a bath condition you can document. Those are also the conditions under which a low-volume, high-mix shop gets predictable results from a process it cannot afford to re-qualify every year.
Decorative gold plating. The same bath finishes small hardware where appearance is the point: jewellery findings, watch components, buckles, nameplates, award fittings, instrument bezels. Because the layer is thin and follows the base metal, it reproduces fine detail and texture instead of filling it in.
A colour layer, not a wear layer. An immersion deposit protects gold plated metal from dulling in storage and handling, but a part that rubs against another part all day will wear through it. Where wear matters, the answer is a thicker electroplated deposit or a protective coat over the top — worth settling before the specification is written, not after.
Architectural aluminium is a different route. Where the visible metal is aluminium — curtain wall, window frames, cladding, handrails — the finish is anodized, and this bath is not part of that process. The anodizing line is covered separately, from degreasing and dewaxing ahead of oxidation through colouring to the sealing agents that close the oxide pores, so a finisher running both aluminium and gold work can source the two from one place.
In PCB manufacturing, precision and reliability come down to how evenly the final coating sits on the board. Electroless nickel plating services provide the uniform coating that high-performance electronics depend on, and building Fengfan Chemical Gilding solutions on top gives manufacturers superior gold plating that improves conductivity and durability. The combined process also shortens production time, which translates into a stronger return for the business. Electroplating equipment suppliers can supply the tools that keep the process consistent and efficient once volumes scale up.
Automotive components have to hold up against salt, moisture and constant vibration, so the coating choice matters as much as the base metal. Zinc nickel plating companies supply coatings built for harsh environmental conditions, while electroless nickel plating services give parts such as gears and shafts the wear resistance and service life the application demands. Aluminum anodizing services add a protective layer that prevents oxidation and keeps the visible finish intact, and anodized aluminum is favored here for being lightweight yet durable.
Choosing the right match is where most sourcing decisions stall. As a trading supplier, we keep one point of contact from first enquiry to after-sales: tell us what you are making and the conditions you work under, and we shortlist the closest matches from our supplier network, compare specifications and arrange samples before you commit to a bulk order. If something does not behave as expected, we work with the supplying partner on the cause and a practical fix, and stay with the case until it is settled. Email, WeChat or WhatsApp enquiries get a reply within 24 hours.
Nickel and nickel alloys. In board work that means the nickel barrier laid over the copper, and the gold only forms where that nickel is exposed and active — which is why the nickel gold plating sequence is a sequence and not an optional extra. It will not deposit directly onto bare copper.
Because the reaction is a displacement, not a reduction. Gold ions exchange with nickel at the surface, and once the nickel is covered there is nothing left to exchange with, so deposition effectively stops. That is what keeps the layer thin, dense and even. If a specification calls for a heavier gold deposit, it needs a different chemistry — this bath is not the route to it.
Yes. The deposit and the bath are the same; what changes is the inspection. On a board you are checking adhesion, thickness control and solderability; on a decorative gold plating job you are checking colour uniformity and that the layer has followed the texture of the part. Both come down to a clean, active nickel surface underneath.
Almost always the surface it lands on. A passive nickel layer, carry-over from the activator, an incomplete rinse, or a bath drifting outside its temperature and pH window all produce the same symptom. Work backwards: check the electroless nickel plating process upstream — activation strength, rinse quality and the time between the nickel and gold tanks — before adjusting the gold bath.
By analysis rather than by counting racks. Gold content is checked and topped up, pH is corrected, temperature is held, and filtration runs continuously. Log every addition: when a colour shift turns up three shifts later, the plating solutions log tells you whether the bath moved or the pre-treatment did.
