FI-7802 is a cyanide-free silver plating process built for lead frames, whether the work stays in-house or is handled by metal plating services. The bath works on the acid side of neutral and deposits silver quickly, which is what makes it usable on a patterned frame inside a production cell rather than in a beaker.
The acidic working range is the part that decides where it fits. A lead frame is normally patterned before it reaches the silver tank, with photoresist defining the windows that receive metal. An alkaline silver bath attacks that resist; this one does not, so frames go in with the resist still on them and come out with the pattern intact.
Silver is rarely the only stage on the line. Frames are cleaned, activated, given a nickel barrier — in-house or from a supplier of electroless nickel plating services — and then silvered, and the final layer is only as good as the stages in front of it — which is why we ask for your full sequence, not just the silver tank, before a bath is specified.
Keeping photoresist intact is the reason this formulation exists. On a patterned lead frame the resist is the mask that decides where silver lands. If a bath lifts, softens or undercuts it, the pattern blurs, silver creeps under the resist edge, and the frame is scrap before it reaches assembly.
Selective work is where this shows up first: a stripe running down the frame, silver on the die-attach and wire-bond pads only, bus bars left bare. Plating shops and silver plating companies that run those patterns keep resist on through several wet stages, and the silver cell is the one where a wrong chemistry announces itself.
Substrate matching is a conversation rather than a fixed list. Lead frames are built from copper alloys with different alloying additions, and the activation and strike ahead of the silver have to suit the alloy you actually buy. Send the alloy designation, the resist type and the smallest opening in the pattern before make-up, and we will say whether the standard sequence needs adjusting. Where the barrier arrives from a supplier of electroless nickel plating services in another plant, its condition at transfer matters as much as its thickness — a passive or oxidised nickel surface gives a patchy first second of deposition even in a well-run bath, so plate a test frame before committing a production lot.
| Property | Characteristic |
|---|---|
| Deposit appearance | Smooth, delicate silver with a fine-grained surface |
| Silver purity | High-purity deposit |
| Deposit hardness | Soft silver layer as plated |
| Throwing power | Good dispersion into fine features and recessed areas |
| Deposition rate | Fast, so a target thickness is reached in a shorter dwell |
| Bath type | Weakly acidic, cyanide-free silver plating solution |
| Photoresist interaction | Does not attack the resist used to pattern lead frames |
| Typical substrate | Copper-alloy lead frames, over a nickel barrier where one is used |
| Finish protection | Anti-tarnish treatment after silver, as with any silver finish |
FI-7802 is a cyanide-free silver plating solution built as a safer alternative for plating plants and chemical suppliers moving away from cyanide chemistry. Its weakly acidic formula produces smooth, uniform silver coatings and does not attack exposed photoresist layers, so patterned substrates pass through the bath without the precision loss that more aggressive chemistries can cause. For operations plating over electroless nickel, that combination of operator safety and dimensional control is what makes the process practical on a working line.
This bath is designed around output. It accelerates deposition rates while still delivering soft, bright silver layers, so higher throughput does not have to come at the cost of appearance or coating consistency. That balance suits high-volume plating factories and chemical raw material operations that need to raise capacity without dropping quality. Share your target deposition rate and line speed with the team so the process can be matched to your equipment.
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.
Lead frames. The bath is a cyanide-free, weakly acidic silver system that lays down silver quickly on a pattern that is already masked with photoresist. It is aimed at frames where the silver has to land on defined windows — die-attach pads, wire-bond pads, a stripe down the strip — and leave the rest of the surface clean.
No. The working bath sits on the acid side rather than the alkaline side, so it does not lift, soften or undercut the resist that masks the frame, and there is no free cyanide in the solution to attack it chemically. Keep the resist specification on file anyway: a resist that is already marginal in its cure can misbehave in any wet line, and it helps to know what you printed before you blame the silver tank.
Copper-alloy lead frames are the main case, with silver usually going on over a nickel barrier. The activation and strike ahead of the silver have to suit the specific alloy, so send us the alloy designation and we will tell you whether the standard sequence needs adjusting. If that barrier comes from a supplier of electroless nickel plating services, share the thickness and how the parts are transferred — both affect how the silver nucleates.
Smooth, delicate and soft, with high-purity silver. Dispersion is good, so the coating follows the fine features of a frame instead of filling only the high-current areas. Silver is a soft metal by nature; if the part needs a harder, wear-resistant silver for repeated mating, another process in the range is the better starting point.
In many cases yes, but the whole sequence has to be checked, not just the tank. Resist type, the barrier underneath, rinse and transfer times and the rectifier's working range all influence the result. A silver plating service moving off cyanide usually starts with a test frame on the new bath before switching a production lot. Send us your current sequence and we will flag what needs to change.
They answer different questions. A bright silver bath is chosen for appearance and a hard silver bath for wear resistance on contacts that mate repeatedly. This plating process is chosen for the substrate and the mask: a weakly acidic bath that plates lead frames quickly and leaves photoresist intact. If your parts are not resist-masked and wear is the concern, one of the other silver systems will suit you better.
Wuhan Fengfan International Trade Co., Ltd., the wholly-owned trading subsidiary of Wuhan Fengfan Electrochemical Technology Co., Ltd., which has worked in surface finishing since 1984. The group researches, develops and manufactures electroplating additives; we handle supply, specification and technical support for customers in electronics, automotive, hardware and general metal finishing.
By controlling the lot rather than the promise. New processes are developed and proven in our pilot plating laboratory before they are offered to a customer line, and production follows documented management standards from raw material intake through to packing. The same bath figures are used from lot to lot, which is what keeps a line that has been dialled in from drifting.
Silver plating chemicals, and the rest of the surface-finishing chain around them: zinc and zinc-nickel brighteners and intermediates, copper processes, electroless nickel, gold and palladium-nickel, tin, passivation, aluminium anodising lines, electrophoretic coatings and nano protective agents. If you are buying a silver plating service rather than a bath, we are the wrong supplier — what we sell is the chemistry and the process support behind it.
Because an answer to a bath problem has to come from someone who can read the analysis. We have been in surface finishing since 1984, we run our own pilot plating laboratory, and the person who replies to your question is the person who knows what the process should look like on a frame. Add a range wide enough to cover the stages either side of silver, and you are not stitching four suppliers together to fix one defect.
Consultation before the bath is specified, a process matched to your frame and line, pilot-scale checks where the part is new to us, quality documentation with each lot, and after-sales support while the bath is running. If a deposit goes wrong we work through the cause with you — bath analysis, sequence, resist, barrier — rather than sending a replacement drum and hoping.
