Pure Nickel FeCl₃+HCl

Chemical Etching Formula
Monel 400 with FeCl₃+HCl

For engineers selecting an etching chemistry for Monel 400, the FeCl₃+HCl formula shown here defines the bath composition, temperature window, and achievable feature sizes across a 0.01-0.3 mm thickness band. Typical mass-production yield for this recipe is 96.3%, with a typical conveyor speed of 2.49 m/min at 50°C.

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+HCl Etchant System
44 °Bé Concentration
1.410 Specific Gravity
50 °C Bath Temperature
Through etch (double-sided) Etch Depth Type
0.01-0.3 mm Thickness Range
0.05 mm Typical Thickness
0.17-59.88 m/min Conveyor Speed Range
2.49 m/min Typical Speed
8-360 μm Min Hole Ø Range
100-300 μm Min Line Width Range
1-57 μm Undercut Range
2.65 Etch Factor (EF)
96.3% Typical Yield (95.6-96.5%)

Why FeCl₃+HCl for Monel 400?

On Monel 400, 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 Monel 400 etch line runs a variant of this formula.

Process Window & Bath Control

Hold the bath at 50°C with concentration 44 °Bé (specific gravity 1.410). Across the 0.01-0.3 mm thickness range, conveyor speed runs from 0.17-59.88 m/min — thinner sheets move faster, thicker sheets slower, in roughly inverse proportion to thickness. A typical mid-range setpoint is 2.49 m/min for 0.05 mm stock. Use redundant PID temperature control to hold the bath within ±1.5°C, and titrate at least once per shift.

Design Rules & Tolerances

When laying out artwork for Monel 400 at through etch (double-sided), plan for a minimum hole diameter in the 8-360 μm range and a minimum line width in the 100-300 μm range, depending on the chosen sheet thickness within 0.01-0.3 mm. The etch factor of ~2.65 and undercut range of 1-57 μm determine how much the mask must be biased to land the finished dimension on target.

Design Rule Summary
• Minimum hole diameter range: 8-360 μm
• Minimum line width range: 100-300 μm
• Single-side undercut range: 1-57 μm
• Typical etch factor (EF): 2.65

Yield & Production Economics

Typical mass-production yield for Monel 400 in the FeCl₃+HCl system is 96.3%, within an observed range of 95.6-96.5%. 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

Typical applications for Monel 400 processed with FeCl₃+HCl include battery tab interconnects, fuel-cell components, and corrosion-resistant masks. The formula's tolerance band and yield make it well suited to medium-to-high-volume precision flat parts.

More Pure Nickel Formulas

Other formulas in the same material family.

Monel K500 FeCl₃+HCl Through etch (double-sided) Ni200 pure nickel FeCl₃+HCl Through etch (double-sided) Ni200 pure nickel FeCl₃+HCl Half etch (single-sided) Ni201 pure nickel FeCl₃+HCl Through etch (double-sided)

Frequently Asked Questions

Single-side undercut ranges 1-57 μm depending on thickness and dwell time. When sizing the photomask for a finished feature on Monel 400, subtract twice the expected undercut from the target width so the etched dimension lands on specification.

Need a Quote for This Process?

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

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