Fengfan SZ-30A is a sulfate acid zinc plating system: a brightener supplied together with the complete bath formulation, so a new line can be started — or an existing one re-balanced — without rebuilding the recipe from scratch. Zinc sulfate heptahydrate and boric acid carry the electrolyte, 0# zinc ingot is the anode, and the brightener governs brightness, leveling and the ductility of the zinc layer.
The same chemistry plates continuous work — wire, strip, tube — and single-piece rack or barrel loads. A plant that runs wire on one shift and loose hardware on the next can keep one tank and change only current settings and racking.
On the part, the result is a smooth, bright, well-leveled zinc deposit. Because the brightener arrives with its formulation, the bath is set up and corrected against known reference points rather than by trial and error — the practical difference between buying a drum of additive and buying a working process.
Fengfan supplies these acid zinc plating chemicals from Wuhan alongside nickel, copper and tin plating lines, aluminium finishing chemicals and surface treatment equipment. The process of electroplating zinc from a sulfate bath is well understood; what varies between suppliers is how closely the brightener and the formulation are matched. Here they are supplied as one package.
| Parameter | Specification |
|---|---|
| Electrolyte system | Sulfate acid zinc |
| Brightener | SZ-30A |
| Zinc sulfate (ZnSO4·7H2O) | 300–450 g/L |
| Boric acid (H3BO3) | 20–30 g/L |
| Brightener dosage | 14–18 ml/L |
| pH | 3.0–4.5 |
| Temperature | 10–50 °C |
| Cathode current efficiency | >95% |
| Anode | 0# zinc ingot |
| Deposit appearance | Smooth, bright, well leveled |
| Work type | Continuous wire, strip and tube; rack and barrel parts |
Brightness is the visible part. What keeps a plated part in service is how the zinc sits on the steel: fine-grained, well bonded and ductile enough to survive the bending, crimping or riveting that happens after plating.
A leveling brightener fills the fine roughness left by stamping and grinding, so a part needs less mechanical polishing before plating and still reads bright after passivation. In electroplating metal parts for visible hardware, that saves a finishing step as often as it saves chemical.
Ductility is the property that is easiest to overlook. A brittle zinc layer cracks at a 90° bend and exposes bare steel at the crack, which becomes the first rust point in service. The organic balance in the brightener keeps the deposit ductile, which matters most on springs, clips and any part that is formed after plating.
Thickness distribution decides whether the minimum is reached in the recesses without overplating the edges. A leveled deposit puts the zinc where it is needed, so less metal is spent on high-current areas and fewer parts are rejected at the thickness check.
A dense, low-porosity layer slows red rust at scratches and takes a passivation film evenly, so colour and coverage stay consistent from part to part. Consistency between batches of brightener is what keeps that appearance the same next month — as much a supply question as a chemistry one.
The bath is built on zinc sulfate, boric acid and an organic brightener. There are no cyanide salts in the formulation, which is the main environmental difference from cyanide zinc plating: no cyanide destruction step in the rinse water and no cyanide in the operators' working environment.
The plating bath itself also contains no hexavalent chromium compounds. If the parts are passivated after plating, that is a separate chemistry — where a customer restricts hexavalent chromium, confirm what the passivation line runs before a finish specification is agreed.
Rinse water from an acid zinc line is handled by pH adjustment and precipitation in the plant's own treatment system, and the process of electroplating zinc this way does not add cyanide complexes to the effluent. Boric acid is the component worth watching, because boron has discharge limits in some regions; check the local permit before scaling up.
For operators, the two exposure points are acid mist at the plating tank and acid mist at the pickling line, both managed with extraction at the tank edge and normal protective equipment. Handling and storage guidance for all electroplating chemicals in this range, including the current safety data sheet, is available from the sales contact.
Cost per plated part is decided at the tank, not at the drum. Three things move it: how much of the current ends up as zinc, how often the bath has to be rebuilt, and how many parts are rejected for appearance. A bath that converts most of its current into metal spends less electricity per kilo of zinc, and a brightener that holds brightness across the whole current density range keeps the reject bin empty.
Rebuilds are the expensive event. A bath that stays in balance through replenishment — salts analysed and topped up, brightener tracked by ampere-hours, filtration kept running — goes far longer between make-ups than one that is corrected only when the parts go wrong.
Then there is the purchasing side. Buying brightener, make-up salts and anodes from one supplier means one freight booking, one set of documents and one technical contact when something drifts. For plants running industrial metal plating across several lines, that consolidation is usually worth more than a few percent on a drum price. The hidden cost is rarely the chemical; it is the shift spent chasing a dull deposit.
Aerospace work on this chemistry is mostly small hardware: fasteners, clamps, bushings, shims, tooling and ground-support equipment. Batches are small, part numbers are many, and the paperwork matters as much as the coating.
What those jobs need from a bath is repeatability — the same deposit on the first part and on the five-hundredth, with thickness controlled closely enough that a thread still gauges after plating. A sulfate zinc bath run at high efficiency with the pH held in range gives that, provided the parts are racked the same way each time and current density is set from surface area rather than from habit.
Hydrogen is the other concern on high-strength steel. High cathode efficiency reduces the amount of hydrogen generated at the work, but it does not remove the need for a baking step where the specification calls for one.
Read the drawing before choosing the process. Where an alloy coating is specified, this straight zinc electrolyte is the wrong choice and the equivalent alloy process should be quoted instead. Apart from that, the metal plating process — cleaning, pickling, plating, passivation — is the same sequence used for any steel hardware.
The process of electroplating small parts in a barrel also means the parts touch each other. Barrel loading, rotation speed and contact quality all affect thickness uniformity, so inspect a first run before fixing the batch size.
Maintenance shops, captive plating lines and rebuild workshops use a sulfate zinc bath because it copes with a mixed bag of work: guards, frames, fasteners, jigs, conveyor components and hand tools. Batch sizes swing from a single part to several hundred.
A bath that keeps its balance through replenishment is worth more here than a marginally faster chemistry, because a shop that plates once a week cannot afford to rebuild the tank every time it runs. Analyse before and after each run, cover the tank when it is idle and keep filtration running between campaigns.
Traceability matters when a plated part goes back into a production machine. Knowing which batch of electroplating chemicals went into the tank, and when, shortens the investigation considerably if a coating later fails in service.
For larger frames and guards, rack plating gives better control over where the zinc lands; for fasteners and small fittings, barrel plating is faster and cheaper. Both run from the same electrolyte, so a maintenance shop does not need two baths.
Repair work is usually judged on turnaround rather than on cosmetic perfection: a clean, well-bonded, adequately thick zinc layer that goes back into service the same week is the goal, and the metal plating process should be planned around that, not around a show finish.
| Minimum order quantity | Varies by chemical; confirmed with our sales team per order |
| Lead time | 2 weeks |
| Payment | 100% T/T in advance |
| Packing | 10 kg/box; 25 kg or 50 kg/bag; 20 kg/25 kg/30 kg/200 kg/drum; 1,000 kg/IBC drum |
| Shipping | Per the terms agreed in the current contract |
| Documentation | Inspection certificate issued after delivery stating the batch number and warranty period |
| Volume and wholesale enquiries | Quoted per order; quantities confirmed with your sales contact |
| Custom requirements | Packing size and labelling discussed per order with your sales contact |
Investing in Fengfan's metal plating services pays back through stronger product performance and lower maintenance costs. Electroless nickel plating and zinc nickel plating shield components from wear and tear, which extends their working life and cuts replacement spending. Aluminum anodizing adds product value and market competitiveness, so the resources you put into finishing go further. Tell us how your parts are used and what they need to withstand, and we will confirm which finish fits the job.
Aerospace manufacturers rely on high-quality aluminum anodizing to strengthen the structural integrity of aircraft components. Collaborating with experienced electroplating equipment suppliers lets them streamline production and apply anodized aluminum coatings consistently from batch to batch. The finish also improves aesthetic appeal and raises resistance to environmental factors. Anodizing techniques help components meet the stringent industry standards that apply to their program, supporting reliability and safety in high-stress environments. Share the specification your parts must satisfy and we will confirm how the process should be set up.
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.
Yes. The electrolyte and the brightener window are the same; what changes is how current reaches the part. On a wire line, start from the running speed and current-per-rod figures for that wire diameter and adjust for the coating weight your customer specifies. On rack or barrel work, set current density from the surface area of the load and rack so the recesses see enough current. Many plants run both from one tank on different shifts, with a rinse and a rack change in between.
Brightener below its working range, zinc metal running low, or insufficient solution movement across the part will all produce burning and dullness where the current density is highest. Confirm the brightener level, then zinc and pH, then run a Hull cell panel to see where in the current density range the dullness begins. If the panel is clean and the parts still burn, look at contacts and racking — a poor contact gives the same symptom as a chemical fault.
Use 0# zinc ingot anodes and keep the anode area matched to the work going through the tank; bagging the anodes keeps fines out of the solution. Continuous filtration pays for itself on any line where appearance matters, because roughness and pitting on an otherwise bright deposit almost always trace back to particles in the bath.
Analyse first: zinc, boric acid, pH and any obvious organic contamination. If the bath is clean and close to the formulation, adjust the salts, bring the brightener into its working range and run a Hull cell panel before production parts go through. If the tank has been running on an unknown brightener for a long time, or the deposit is dark and brittle, a fresh make-up is usually faster than trying to correct the old bath.
No. This is a straight zinc sulfate electrolyte and the deposit is zinc, not a zinc alloy. Where a drawing specifies zinc nickel plating for a higher corrosion duty, that is a different bath with its own addition system and should be quoted as such — the two cannot be swapped by adding one more component to the tank.
No. Chloride zinc electrolytes use a different carrier and brightener set, and a sulfate brightener added to a chloride bath will not give the same brightness or the same throwing power. Match the brightener to the electrolyte already in the tank; if the plant runs both chemistries, they need two separate baths and two separate additive lines.
Yes, and a leveled bright deposit takes those finishes more evenly than a rough one. Clear and blue passivations hold their colour better when the underlying zinc is uniform, and lacquer or paint bonds to a clean, level surface. Confirm the passivation chemistry separately if your customer restricts hexavalent chromium, since that step is not part of this plating bath.
