Chemical Etching Formula
C7521 Nickel Silver with FeCl₃+HCl

Formula Summary

The table below summarizes every parameter that defines this etching formula. Values listed as ranges scale with sheet thickness across the supported band.

Why FeCl₃+HCl for C7521 Nickel Silver?

On C7521 Nickel Silver, the ferric chloride system attacks the alloy's oxide layer continuously while ferric ions drive dissolution. It is regenerable, compatible with standard photolithography, and produces clean burr-free edges — which is why nearly every C7521 Nickel Silver etch line runs a variant of this formula.

Process Window & Bath Control

Bath control for C7521 Nickel Silver in FeCl₃+HCl: temperature 46°C, concentration 42 °Bé, specific gravity 1.390. The recipe is tuned for through etch (double-sided). Conveyor speed is the primary throughput control, ranging 0.2-2.97 m/min across the supported thickness range. Check specific gravity each shift with a calibrated hydrometer and correct with fresh make-up or water as needed.

Design Rules & Tolerances

Design rules for this recipe: hole diameter 60-360 μm, line width 100-300 μm, single-side undercut 9-56 μm — all as a function of thickness across 0.05-0.3 mm. The higher the etch factor (this formula holds about 2.70), the tighter the achievable tolerance. Below the minimum feature sizes, yield falls off steeply, so treat those numbers as hard floors rather than targets.

Yield & Production Economics

Expect a yield in the 96.8-97.4% range for C7521 Nickel Silver with FeCl₃+HCl, with 97.1% typical on a well-controlled line. Most rejects trace back to upstream coating and exposure rather than to the etch bath itself, so tightening photolithography control is usually the fastest path to a higher number.

Typical Applications

Typical applications for C7521 Nickel Silver processed with FeCl₃+HCl include lead frames, busbars, flexible heater elements, RF gaskets, and precision electrical contacts. The formula's tolerance band and yield make it well suited to medium-to-high-volume precision flat parts.

Process Equipment & Material Reference

Process equipment for the C7521 Nickel Silver / FeCl₃+HCl combination is built around our knife-mold etching machine platform — closed-loop temperature control, redundant pump headers, and metering for bath replenishment all directly affect the etch factor and yield numbers cited on this page.

If you need a wider view of silver beyond this single recipe, our Silver chemical etching guide covers grade selection, photoresist compatibility, and typical industries that consume this metal in etched form.

Production Use Cases for This Formula

Across the markets we serve, the FeCl₃+HCl formula on this page is most often deployed for cold-press juicer filtration mesh, stainless steel shower-head filter mesh, and soy-milk-maker filtration mesh. These applications share thin-feature geometries that benefit from the predictable etch factor near 2.70 and the low single-side undercut documented above.

Designs that sit slightly outside this thickness or feature-size envelope are usually addressable by a sister formula in the same etchant family. The bath chemistry stays the same; the tuning shifts to conveyor speed and resist choice.

Other Metals Etched with FeCl₃+HCl

The FeCl₃+HCl chemistry is also documented for these alloys.

More Copper & Brass Formulas

Other formulas in the same material family.

Frequently Asked Questions