PP Corrosion Inhibitor is an alkynol-derivative corrosion inhibitor for acid cleaning, acid derusting and acid scale removal. It is supplied as a clear, light yellow to yellow transparent liquid and is dosed into the working acid bath.
A pickle tank is judged on two things at once: whether the oxide is gone, and what happened to the metal underneath while it was going. This product is added to the working bath to hold the second of those in check, without changing the bath, the tank or the sequence the line already runs.
Steel, copper and aluminum are the substrates it was formulated for, and between them they cover most of what passes through an acid cleaning line. Carbon and low-alloy steel is the largest group by volume: stampings, fasteners, tube, machined components. Copper busbar, contacts and connector shells are cleaned in acid where oxide has to come off without pitting the surface. Aluminum sheet, extrusions and castings are pickled or deoxidised ahead of finishing, and aluminum is the substrate that punishes an uncontrolled acid bath fastest. Parts leave the tank and go on to plating solutions, anodizing, painting or assembly, and what the pickle left behind is what those processes inherit.
Because it is a bath additive and not a coating, a passivation step or a piece of equipment, it goes into the tank and the rinse train you already run. Nothing in the line has to be re-laid out. Shops running industrial metal plating alongside pickling tend to start here: one barrel, dosed by drum pump or by hand, protecting every substrate the line handles.
| Property | Value |
|---|---|
| Product name | PP Corrosion Inhibitor |
| Chemical nature | Alkynol derivatives |
| CAS number | 3973-17-9 |
| Appearance | Light yellow to yellow transparent liquid |
| Solid content | 65–69% |
| pH | 7.0–7.5 (10% aqueous solution) |
| Substrates | Steel, copper, aluminum |
| Typical dosage | 5–50 g/L |
| Formulation systems | Acid cleaning; acid derusting and scale removal |
| Packaging | 25 kg plastic barrel |
| Storage | Cool and dry place, barrel kept closed |
Alkynol inhibitors work by adsorption. In the tank, the molecules take up positions on the metal surface and build a thin barrier at the interface where acid would otherwise dissolve the base metal. The barrier is dynamic rather than a coat: it forms where clean metal is exposed and is much less effective on the oxide, rust and scale the bath is there to remove — which is why descaling carries on while metal loss falls.
On steel, the substrate that dominates most acid cleaning tanks, the result is controlled pickling. Mill scale, heat-treat oxide and rust come off; machined faces, threads and edges underneath keep their dimensions. The pickle also sets the surface that the plating solutions build on, and a bath left running too long is one of the common reasons a batch plates unevenly.
That matters just as much in electroless plating, where coverage on a complex part depends entirely on what the surface looked like going in. An over-pickled surface and an under-pickled one often produce the same symptom at inspection: patches.
Copper behaves differently. Acid cleaning of busbar, contacts and connector shells has to lift oxide without pitting the surface, and copper dissolves readily in strong acid once the oxide is gone. The inhibitor widens the gap between clean and etched, and the same applies to brass parts and copper-plated work being prepared for the next step.
Aluminum needs the most help. It is amphoteric — attacked by acid about as readily as by alkali — and sheet, extrusions and castings can lose surface and develop a mottled etch while the bath is doing its job on the oxide. With the inhibitor present, gassing at the surface is calmer and the metal that comes out is even, which is the state it needs to be in before anodizing, conversion coating or zinc nickel plating.
Two effects follow from lower metal dissolution: less gas is generated at the part surface during the reaction, and less dissolved metal builds up in the bath. Both show up later as a bath that stays usable for longer and a rinse that has less to carry away.
The product is used in the two systems it was developed for — corrosion inhibition in acid cleaning, and corrosion inhibition for rust and scale removal in acid systems. The chemistry is the same in both; the acid, its strength and the dwell time decide where in the 5–50 g/L range your bath sits.
Nothing here is designed to be aggressive. In 10% aqueous solution the product sits at pH 7.0–7.5, so the concentrate is close to neutral and does not bring a second acid load into the building or onto the operator's gloves. It is a clear liquid that pours and meters easily at room temperature, from the 25 kg barrel with a drum pump or by hand into a measuring jug ahead of the tank.
Because it works at 5–50 g/L, the dose can be trimmed to what the job needs. A line running light oxide and a two-minute immersion does not need the top of the range; a heavy-scale bath with a long dwell does. Buying to the job rather than to the maximum is the simplest environmental measure on a pickling line, and it is also the cheapest.
Lower metal dissolution has a second effect that matters at the effluent plant. In industrial metal plating the pickle is usually the tank carrying the highest dissolved-metal load, so a bath that dissolves less of the work also sends less to the rinse water and produces less sludge between dumps. That eases the water balance for the whole line, not just for one tank.
What the product does not do is replace waste treatment. Spent acid baths still go through the neutralisation, settlement and disposal route your plant already follows, under the rules that apply where you operate. Treat dosing as a way to reduce the load, not as a way to skip the treatment step.
Storage is simple: keep the barrel closed in a cool, dry place, out of direct sun. Under those conditions the product stays as supplied and the figures on the label still describe what is in the drum.
Acid cleaning looks the same from the outside and is completely different inside each industry. In a metal plating process the pickle is judged on what the next tank receives; in maintenance descaling it is judged on whether the wall of the vessel survives. The product is the same; the dose and the dwell are not.
Automotive components
Gears, shafts, fasteners, stampings and suspension hardware are pickled before plating, and often before zinc nickel plating where the corrosion target is high. A bearing seat that has lost a couple of microns to over-pickling does not go back on the drawing, which is why the acid tank gets more attention here than its position in the line suggests.
Electronics manufacturing
Connector shells, shields, stamped contacts and lead frames are acid cleaned before electroless nickel plating, where coverage on a thin part depends on a surface free of smut and stamping residue. High surface area in a small bath volume also means the tank loads quickly, so the inhibitor dose has to be right rather than merely present.
Aerospace components
High-strength steel fittings, actuators and structural parts carry heat-treat oxide that has to come off without introducing surface defects. These parts often go on to electroless plating or another protective finish, and the surface condition set in the acid tank travels with them all the way to final inspection.
Industrial equipment maintenance
Heat exchangers, water jackets, pipework, tanks and machine frames are descaled in place, with acid circulated through the system until the scale is gone. The sound steel wall has to survive the same acid that is dissolving the deposit — this is the case where an uninhibited acid does the most expensive damage, and where the dose is usually set at the top of the range.
Architectural metalwork
Aluminum extrusions, façade panels, balustrades and decorative sections are deoxidised and pickled before aluminum anodizing, and steel elements are cleaned before plating or coating. An uneven pickle shows through an anodized finish; an even one does not, which is why this sector judges the bath on appearance at ten paces.
Mixed job shops
A shop that takes in whatever the customer sends — steel one day, aluminum the next — needs one inhibitor that covers all three substrates rather than three products and three dose cards. That is the case this single-barrel approach was built for.
Architectural metalwork usually has to deliver appearance and durability at once, and anodised aluminium is a common choice for facades and decorative elements because of its corrosion resistance and the range of finishes available. Aluminium anodizing gives architects colour and texture options to work with, so design intent and long-term performance of the metal can be resolved together.
Most projects begin with three questions: what the part is made of, what it will be exposed to, and what the finished surface has to look like. A steel gear or shaft running under load is a different case from an aluminium trim piece chosen mainly for its appearance, and a part that sits outdoors in the weather needs a different answer from one that is handled constantly on a line. Sharing the base metal, the expected service conditions and any cosmetic requirement is usually enough to narrow the choice between aluminium anodizing, electroless nickel plating, zinc nickel plating and alodine coating. Where the part sits inside a customer's own drawing or specification, it is worth confirming that requirement with us before the finish is fixed, since the acceptance criteria live in the drawing rather than in the name of the coating.
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.
Steel, copper and aluminum. Steel is the main volume — carbon and low-alloy parts, machined components, tube and fasteners in acid cleaning and derusting baths. Copper covers busbar, contacts and connector shells, where oxide has to come off without pitting the surface. Aluminum gains the most, because acid attacks it quickly once the oxide is gone; sheet, extrusions and castings come out with a more even surface and calmer gassing.
Match it to how hard the bath is working. Light oxide and a short immersion sit at the low end; heavy scale, long dwell times and dense loads of small parts sit at the top. If the bath is already carrying a lot of dissolved metal, or the acid strength has been pushed up to shorten the cycle, move up the range rather than extending the time. Send us the acid type, the substrate and your cycle and we will tell you where we would start.
No. CAS 3973-17-9 appears on two of our grades with different specifications and different jobs. This PP Corrosion Inhibitor is the acid-cleaning grade. The brightener grade is a different concentration, sits at a different pH and is dosed in millilitres per litre into a nickel bath. If you are unsure which one your process needs, describe the bath and we will confirm.
It stays in the tank rather than on the work. Parts leave the acid bath and pass through the rinse stage the line already runs, and what goes to the next tank is the pickled surface itself. Where the next step is electroless nickel plating or anodizing — both of which show surface condition very clearly — keep the rinse as you would for any acid bath and check the first rack before running the whole load. Blind holes and tightly packed bundles need the same extra attention they always do.
Yes — those are the two formulation systems it is made for. Acid cleaning lifts light oxide and shop soil; acid derusting and scale removal runs a stronger bath for longer to take off mill scale, heat-treat oxide and rust. The inhibitor handles both, but the harsher the bath, the more the dose matters, so a descaling bath usually sits nearer the top of the 5–50 g/L range than a light cleaning bath does.
The concentrate is close to neutral, so at a working dose it adds very little acid or alkali to the tank. Measure free acid after the first charge as you normally would and adjust the acid, not the inhibitor, if the figure has moved. The inhibitor dose is set by the substrate and the workload, not by the acid number.
