Copper & Brass FeCl₃

Chemical Etching Formula
C5101 phosphor bronze with FeCl₃

This reference describes how C5101 phosphor bronze responds to the FeCl₃ etching formula. At a bath temperature of 46°C and concentration of 40 °Bé, the recipe holds an etch factor of about 2.74 and a typical production yield of 97.4%. It is intended as engineering reference data for design, sourcing, and process planning.

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.

FeCl₃ Etchant System
40 °Bé Concentration
1.380 Specific Gravity
46 °C Bath Temperature
Through etch (double-sided) Etch Depth Type
0.05-0.5 mm Thickness Range
0.20 mm Typical Thickness
0.12-2.77 m/min Conveyor Speed Range
0.40 m/min Typical Speed
60-600 μm Min Hole Ø Range
100-500 μm Min Line Width Range
9-91 μm Undercut Range
2.74 Etch Factor (EF)
97.4% Typical Yield (96.7-97.8%)

Why FeCl₃ for C5101 phosphor bronze?

On C5101 phosphor bronze, 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 C5101 phosphor bronze etch line runs a variant of this formula.

Process Window & Bath Control

Bath control for C5101 phosphor bronze in FeCl₃: temperature 46°C, concentration 40 °Bé, specific gravity 1.380. The recipe is tuned for through etch (double-sided). Conveyor speed is the primary throughput control, ranging 0.12-2.77 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 60-600 μm, line width 100-500 μm, single-side undercut 9-91 μm — all as a function of thickness across 0.05-0.5 mm. The higher the etch factor (this formula holds about 2.74), the tighter the achievable tolerance. Below the minimum feature sizes, yield falls off steeply, so treat those numbers as hard floors rather than targets.

Design Rule Summary
• Minimum hole diameter range: 60-600 μm
• Minimum line width range: 100-500 μm
• Single-side undercut range: 9-91 μm
• Typical etch factor (EF): 2.74

Yield & Production Economics

Expect a yield in the 96.7-97.8% range for C5101 phosphor bronze with FeCl₃, with 97.4% 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

C5101 phosphor bronze etched with this recipe typically ends up in lead frames, busbars, flexible heater elements, RF gaskets, and precision electrical contacts. Because chemical etching applies no mechanical or thermal load, the finished features are free of work-hardening and heat-affected zones — a decisive advantage over stamping or laser cutting for these uses.

More Copper & Brass Formulas

Other formulas in the same material family.

C1020 OF Copper FeCl₃ Through etch (double-sided) C1100 T2 copper FeCl₃ Through etch (double-sided) C1100 T2 copper FeCl₃ Through etch (double-sided) C1100 T2 copper FeCl₃ Through etch (double-sided) C1100 T2 copper FeCl₃ Through etch (double-sided) C1100 T2 copper FeCl₃ Half etch (single-sided)

Frequently Asked Questions

Yes. Wet chemical etching is a non-contact chemical process with no mechanical cutting or thermal input, so etched C5101 phosphor bronze features are completely free of burrs, work-hardening, and heat-affected zones. That edge quality is the defining advantage over stamping or laser cutting for precision flat parts.

Need a Quote for This Process?

WET Etched runs production wet chemical etching lines using the FeCl₃ chemistry. Send us your part drawing and quantity for a full process quote.

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