FlowMarket
Where to source electroplating and galvanizing: FlowMarket is a B2B sourcing network powered by an AI agent. You describe the job — substrate and its strength, coating system and layer thickness, passivation and sealing, required salt spray performance, part geometry, hydrogen embrittlement relief needs and quantity — and the AI agent matches you with verified plating and galvanizing job shops, then requests prices and lead times from every match at once. Getting matched is free for buyers.
Sourcing electroplating and galvanizing
Electroplating deposits a metal layer from solution onto a conductive part, giving corrosion protection, wear resistance, conductivity or appearance depending on the metal chosen. Hot-dip galvanizing is a different process for the same broad purpose — immersion in molten zinc, producing a much thicker and more robust layer for structural steel.
What both share is that the specification is a system, not a metal. Layer thickness, passivation, sealing and any post-treatment are separate decisions that together determine corrosion performance, and quoting only "zinc plated" leaves all of them open.
Coating systems
Zinc and zinc alloys
Zinc plating is the workhorse for steel, protecting sacrificially so that the zinc corrodes before the substrate. Plain zinc with a passivation gives useful protection at low cost; zinc-nickel alloys reach far higher salt spray performance and hold up better at temperature, which is why automotive under-bonnet parts use them widely. Zinc flake coatings are applied without electrolysis and avoid hydrogen embrittlement entirely.
Nickel, chrome and electroless nickel
Nickel gives a bright, corrosion-resistant decorative layer and a base for chrome. Hard chrome builds a thick, very hard surface for wear parts such as hydraulic rods, usually ground to final size afterwards. Electroless nickel deposits chemically rather than electrically, so it coats to a uniform thickness even inside bores and recesses where an electroplated layer would thin out.
Hot-dip galvanizing and others
- Hot-dip galvanizing — immersion in molten zinc to EN ISO 1461; thick, tough, for structural steel.
- Tin — solderability and food-contact suitability.
- Copper — an underlayer for adhesion and levelling, or for electrical conductivity.
- Silver & gold — contact surfaces in electrical and electronic assemblies.
What to specify when sourcing
These details decide both the process and the price:
- Substrate — material and, for steel, its strength or hardness; this drives embrittlement risk.
- Coating system — metal, alloy and the standard it must meet, with the full designation.
- Layer thickness — target in µm and where it is measured, including in recesses.
- Passivation & sealing — required conversion layer and any topcoat or sealer.
- Corrosion requirement — salt spray hours to white and to red rust, per ISO 9227.
- Part geometry — blind holes, threads, tight recesses and anything that traps solution.
- Dimensional effect — tolerances on threads and fits after plating.
- Embrittlement relief — required for high-strength steel; state hardness or tensile strength.
- Handling — barrel or rack, and whether contact marks are acceptable.
- Compliance & volume — RoHS and ELV restrictions, friction coefficient for fasteners, batch size and annual quantity.
Hydrogen embrittlement and the thickness that changes the fit
The most serious risk in electroplating is invisible at delivery. Acidic pickling and plating release hydrogen, which diffuses into high-strength steel and can cause sudden brittle failure days or weeks later under load — a fastener that passed inspection snapping in service. It is prevented by a relief bake soon after plating, typically within a few hours, and by choosing processes that generate less hydrogen or none at all, such as zinc flake coatings. This matters for hardened and high-tensile parts, so state the material's strength or hardness in the enquiry rather than leaving the plater to guess. The second issue is dimensional. Plating adds material to every surface, and on a thread the effect on the pitch diameter is several times the nominal layer thickness, which is enough to turn a comfortable fit into an interference. Say which surfaces are dimensionally critical and whether they were machined to allow for the coating. Related to both: chromium(VI) passivation, the traditional yellow chromate, is restricted under RoHS and ELV, so a drawing that still calls for it needs updating to a chromium(III) system — worth checking before it becomes a delivery dispute.