This is a brightener for sulfate zinc plating, the acid zinc family built on zinc sulfate and boric acid rather than on caustic soda. In the tank it governs how the zinc grains grow: dosed correctly it produces a deposit that is smooth, bright and well levelled, and it holds that finish from the first part of a shift to the last. Wire galvanizing is the classic home of this metal plating process, but the brightener is just as much at home on a rack line where parts are plated one load at a time. We supply it together with the zinc sulfate and the boric acid as one package of acid zinc plating chemicals, so a tank can be charged from a single order instead of being pieced together from several sources. The formulation is deliberately short, which makes the bath quick to analyse, easy to hand over between shifts, and simple to correct when a number drifts out of band.
| Item | Operating Range | Standard Value |
|---|---|---|
| Zinc sulfate (ZnSO₄·7H₂O) | 350–450 g/L | 450 g/L |
| Boric acid (H₃BO₃) | 25–35 g/L | 30 g/L |
| SZ-30B brightener | 20–30 ml/L | 25 ml/L |
| pH | 2.5–3.5 | 3.0 |
| Temperature | 10–50 °C | 15–35 °C |
| Cathode current efficiency | >95% | >95% |
| Anode | No. 0 zinc ingot | No. 0 zinc ingot |
| Parameter | Reference value |
|---|---|
| Wire diameter up to 1 mm — running speed | 10–30 m/min |
| Wire diameter up to 1 mm — current intensity per wire rod | 20–80 A |
| Wire diameter up to 2.5 mm — running speed | 7–20 m/min |
| Wire diameter up to 2.5 mm — current intensity per wire rod | 120–350 A |
| Wire diameter up to 5 mm — running speed | 5–10 m/min |
| Wire diameter up to 5 mm — current intensity per wire rod | 200–500 A |
| Largest wire diameter covered by this data | 5 mm |
| Running speed expressed as | Metres of wire travel per minute through the bath |
| Current intensity expressed as | Amperes applied to a single wire rod |
| Adjustment variables | Wire diameter, line speed, bath condition and the plating result required |
A wire line is judged on the coil, not on a test panel, and the settings that produce a good coil come from diameter, line speed and current together rather than from a single recipe. The reference table gives the bands to start from; expect to trim them for your line geometry, your bath age and the finish your customer asks for. Set current against wire diameter before you touch line speed. A thin wire and a heavy rod do not take anything like the same current, and pushing a thin wire towards a heavy-rod current burns the deposit and leaves it brittle. Match anode area to the load as well: a heavy wire order pulls a large current, so check anode bags, anode area and contact bars before the line speed goes up. Drag-out is the quiet variable on a continuous line. Wire carries bath out of the tank all shift, so volume and concentration fall steadily; build the top-up into the routine instead of reacting to a dull patch at the end of the run. Keep the entry clean as well — drawing lubricant or grease carried into the bath shows up as bare patches and poor adhesion, and no addition will fix a cleaning problem on an electroplating line.
Brightness and levelling are judged on the part, not in the bath: the finished component is the only honest measure of the process of electroplating, and a panel kept from a known-good run is the cheapest instrument a plating shop owns. Pull a sample at the start of the shift and another after the bath has run for a few hours, and compare both against that panel. Thickness and corrosion performance depend on how the whole plating process is run, not on the brightener alone. The steel substrate, the deposit thickness you aim for and whatever passivation or sealing follows the zinc all move the result, which is why we do not publish a single salt spray figure for this product. Tell us the substrate, the thickness you target and the post-treatment you use, and we will agree the test method with you, so the number you pass to your own customer is one your line can reproduce. If appearance is the acceptance criterion, fix the light and the viewing angle and keep them the same every shift. Zinc brightness reads differently under a sodium lamp and under daylight, and a fair share of arguments about a dull batch turn out to be arguments about the light.
The brightener is supplied as an additive in drums. Keep containers closed and under cover, off direct sunlight and away from strong oxidisers, and stand them off the floor so a damp store does not corrode the base of the drum. Acid sulfate baths are handled like any other electroplating chemistry on site: eye protection, acid-resistant gloves and an apron for decanting, and a bund or tray under the drum while it is being tapped. Read the safety data sheet and the drum label before the first drum is opened. If you need a copy for your own records or for a customer audit, ask your sales contact and we will send the current version for the batch you have received. Write the batch number from the label into your bath log. If a question comes up later about a delivery — a colour difference, a slower response than you expected — that number is what lets us trace the batch, compare it with what else went out at the same time and give you an answer instead of a guess.
Technical questions about a running bath are answered by the team that supplies the brightener. When you write, tell us where in the plating process the problem appears — brightness, adhesion, coverage in a recess, a current that will not climb — and add the bath volume, the type of line you run (wire, rack or barrel), the substrate and your destination. Those details are usually enough for a useful answer on the first reply rather than a round of questions. If you are planning a new tank or changing an existing bath, send the make-up and the operating figures you run today. We will set them against the standard values for this product and tell you what to move, which is a much shorter conversation than a metal plating process rebuilt by trial and error.
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.
It is made for sulfate zinc plating: a bath built on zinc sulfate as the metal source and boric acid as the buffer, running on the acid side. It is not intended for alkaline zinc or for chloride zinc systems, which use different addition agents and hold a different pH.
The working range is 20–30 ml/L, with 25 ml/L as the standard figure. Start at the standard value on a new bath, judge the result on a test panel, and add in small increments rather than jumping straight to the top of the range.
Hold pH between 2.5 and 3.5, with 3.0 as the standard. The bath works between 10 °C and 50 °C, and the standard operating band is 15–35 °C. The wider range is there for cold mornings and warm afternoons, not as a target to run at.
No. 0 zinc ingot. Keep anode area and contact bars in good order as well, because a sulfate bath with a lazy anode shows up as a current that will not reach its set point and a deposit that loses brightness at the far end of the rack.
Yes. Reference running speed and current intensity values are published for wire diameters up to 5 mm, and they are starting points: the final setting follows wire diameter, line speed, bath condition and the finish you need.
Usually at the bath rather than at the brightener. Work through pH, temperature and zinc sulfate concentration before adding more additive, then check for iron or copper pick-up and for anode area. A plating process that has drifted will not be corrected by brightener alone, and over-addition makes the next correction harder.
Often yes, but it should not be a blind swap. Changing additive inside a running bath is one of the less forgiving moves in the process of electroplating, because old and new components can behave differently at the same concentration. Send us your current make-up and operating figures, and run a panel test before the production bath is changed over.
Analyse it on a fixed schedule rather than when something goes wrong. Boric acid is the buffer that holds pH steady; when it falls low, pH swings between checks and the deposit burns at high current density. Top up towards the standard figure and re-read pH after the addition.
Yes — the brightener sits in a range of acid zinc plating chemicals that includes the salts and the anode specification, so a new tank can be charged from one order. Tell us the bath volume and we will match the quantities to the make-up figures.
Sulfate zinc deposits are normally passivated or sealed after plating, and the finish from this brightener is smooth enough to take a routine post-treatment. Tell us which passivation system you use and we will confirm the sequence with you rather than assume it.
