The Export Shipment That Arrived Black

We supply finishing chemicals to silver jewellery manufacturers across India. So we get the phone calls the ones that come after something has gone wrong.

Three weeks ago, one of those calls came from Jaipur.

"Export shipment arrived black. Customer is refusing the lot. What do we do?"

Beautiful oxidised silver pieces. Perfect when they left the factory. Four weeks on a ship to Europe. Black tarnish on arrival.

And here's the thing this wasn't an isolated incident.

Mumbai mentioned similar issues. A brass jewellery exporter from Moradabad said green oxidation was showing up before containers even reached port. Chennai reported returns from a Dubai buyer pieces tarnished before they hit the retail display.

Different metals, different destinations, same problem.

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Why standard protection fails

Here's what we've learned from years of these calls: the protection most people use isn't designed for the journey their pieces actually take.

Anti-tarnish bags? They work while pieces are inside them. Open the bag, protection ends. Showroom mein piece rakh do, tarnishing shuru.

Lacquer? Yellows over time. Peels at stress points. Customers notice and they don't like it.

Wax coatings? Change the feel of the piece. That smooth, premium touch becomes waxy. Buyers can tell.

The real problem isn't lack of protection. It's the wrong kind of protection.

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Protection you can't see, touch, or feel

OXIFEND5 is a chemical passivation from Legor. Not a coating. Not a film. A molecular-level barrier that bonds directly to the metal surface.

How thin? 0.001 to 0.01 micrometres. That's 100 times thinner than a human hair. Completely invisible. No colour change. No texture change. Customer ko pata bhi nahi chalega protection hai.

What it blocks: hydrogen sulphide (the gas in air that turns silver black), UV exposure, sweat, humidity. The things that attack your pieces during shipping, storage, and retail display.

What it works on: silver, brass, bronze, low karat gold, electroplated surfaces. One solution for your whole production line.

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The practical side

Application is a simple dip 5 to 20 minutes at 50-60°C. Warm bath, not hot. No special equipment needed. For chains and complex pieces, electrolytic application reaches hidden areas that dip can't.

The concentrate is 20X concentrated 250ml makes 5 litres of working solution. Lower storage cost, lower shipping cost per litre.

Bonus we didn't expect: the passivation layer has lubricating properties. Pieces slide easier during handling and assembly. Small thing, but production teams notice.

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What this depends on

I'll be upfront about limitations.

If your pieces aren't properly cleaned before passivation, the bond won't form correctly. Oil residue, polishing compound, fingerprints they all interfere. Clean surface, strong bond. Dirty surface, weak protection.

And if you're working with high-karat gold 18KT and above you probably don't need this. High-karat gold doesn't tarnish significantly. This is for silver, brass, bronze, and lower karat gold where tarnishing is actually a problem.

Par agar aapki cleaning process solid hai if pieces are properly degreased before treatment then passivation gives you protection that travels with the piece. Storage, shipping, retail display. The barrier stays on.

Worth a trial?

If export shipments are arriving tarnished, or showroom inventory is going black before it sells, or you're spending labour hours on re-polishing it might be worth testing.

Apply OXIFEND5 to one batch. Store alongside untreated pieces in the same conditions. Compare after four weeks. The difference will be visible.

Reach out: help@preciousalloy.com  |  +91 22 6101 4444