Precision Alloys FeCl₃+HCl

Chemical Etching Formula
Ni42 Alloy with FeCl₃+HCl

This page documents the reference wet chemical etching formula for Ni42 Alloy using the FeCl₃+HCl system. The recipe below covers a sheet-thickness range of 0.05-0.3 mm and is configured for through etch (double-sided). Every value is drawn from operational process records rather than theoretical calculation, and is provided as a starting point for your own process development.

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
0.05-0.3 mm Thickness Range
0.15 mm Typical Thickness
0.19-2.77 m/min Conveyor Speed Range
0.67 m/min Typical Speed
60-360 μm Min Hole Ø Range
100-300 μm Min Line Width Range
9-54 μm Undercut Range
2.76 Etch Factor (EF)
96.6% Typical Yield (96.1-96.8%)

Why FeCl₃+HCl for Ni42 Alloy?

On Ni42 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 Ni42 Alloy etch line runs a variant of this formula.

Process Window & Bath Control

The process window for this FeCl₃+HCl formula centres on 50°C and 44 °Bé. Conveyor speed spans 0.19-2.77 m/min over the 0.05-0.3 mm thickness band; the typical operating point is 0.67 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

Feature sizes scale with sheet thickness. For this formula the minimum hole diameter ranges 60-360 μm and the minimum line width ranges 100-300 μm across the 0.05-0.3 mm band, following the industry 1.2× (hole) and 1.0× (line) thickness rules. Single-side undercut ranges 9-54 μm, and the etch factor is about 2.76. Size your photomask by subtracting twice the expected undercut from each finished feature dimension.

Design Rule Summary
• Minimum hole diameter range: 60-360 μm
• Minimum line width range: 100-300 μm
• Single-side undercut range: 9-54 μm
• Typical etch factor (EF): 2.76

Yield & Production Economics

Typical mass-production yield for Ni42 Alloy in the FeCl₃+HCl system is 96.6%, within an observed range of 96.1-96.8%. 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

Ni42 Alloy etched with this recipe typically ends up in hermetic sealing rings, lead frames matched to glass/ceramic, and magnetic shielding. 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 Precision Alloys Formulas

Other formulas in the same material family.

1J22 Iron-Cobalt Alloy FeCl₃+HCl Through etch (double-sided) 1J46 Permalloy FeCl₃+HCl Through etch (double-sided) 1J50 Permalloy FeCl₃+HCl Through etch (double-sided) 1J79 Permalloy FeCl₃+HCl Through etch (double-sided) 1J85 Super-Permalloy FeCl₃+HCl Through etch (double-sided) HyMu80 (Permalloy) FeCl₃+HCl Through etch (double-sided)

Frequently Asked Questions

Both standard dry-film photoresists (typically 1.5–2.0 mil) and aqueous-developable liquid resists are compatible with FeCl₃+HCl at 50°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+HCl chemistry. Send us your part drawing and quantity for a full process quote.

Request a Quote Browse Formulas