Copper & Brass FeCl₃

Chemical Etching Formula
C194 Copper-Iron Alloy with FeCl₃

The FeCl₃ chemistry is a proven formula for C194 Copper-Iron Alloy. This reference sheet lists the concentration (36 °Bé), specific gravity (1.340), bath temperature (46°C), and the full range of conveyor speeds and feature tolerances that result. Use it to size your process before committing to a production trial.

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
36 °Bé Concentration
1.340 Specific Gravity
46 °C Bath Temperature
Through etch (double-sided) Etch Depth Type
0.1-0.3 mm Thickness Range
0.20 mm Typical Thickness
0.25-1.15 m/min Conveyor Speed Range
0.44 m/min Typical Speed
120-360 μm Min Hole Ø Range
100-300 μm Min Line Width Range
18-54 μm Undercut Range
2.80 Etch Factor (EF)
97.5% Typical Yield (97.2-97.8%)

Why FeCl₃ for C194 Copper-Iron Alloy?

On C194 Copper-Iron Alloy, 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 C194 Copper-Iron Alloy etch line runs a variant of this formula.

Process Window & Bath Control

The process window for this FeCl₃ formula centres on 46°C and 36 °Bé. Conveyor speed spans 0.25-1.15 m/min over the 0.1-0.3 mm thickness band; the typical operating point is 0.44 m/min. Every 5°C drop in bath temperature requires roughly a 30% reduction in conveyor speed to hold the same etch depth, so temperature stability is the single biggest lever on consistency.

Design Rules & Tolerances

When laying out artwork for C194 Copper-Iron Alloy at through etch (double-sided), plan for a minimum hole diameter in the 120-360 μm range and a minimum line width in the 100-300 μm range, depending on the chosen sheet thickness within 0.1-0.3 mm. The etch factor of ~2.80 and undercut range of 18-54 μm determine how much the mask must be biased to land the finished dimension on target.

Design Rule Summary
• Minimum hole diameter range: 120-360 μm
• Minimum line width range: 100-300 μm
• Single-side undercut range: 18-54 μm
• Typical etch factor (EF): 2.80

Yield & Production Economics

Typical mass-production yield for C194 Copper-Iron Alloy in the FeCl₃ system is 97.5%, within an observed range of 97.2-97.8%. The dominant yield-loss modes are photoresist pinhole defects and rinse-water contamination. Improving incoming sheet quality and photoresist coating consistency gives the highest yield-improvement leverage for this formula.

Typical Applications

C194 Copper-Iron Alloy 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

Both standard dry-film photoresists (typically 1.5–2.0 mil) and aqueous-developable liquid resists are compatible with FeCl₃ at 46°C. Resist choice is driven by resolution: features near the fine end of the 100-300 μm line-width range usually call for liquid resist, while larger features can use lower-cost dry film.

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.

Request a Quote Browse Formulas