Precision Alloys FeCl₃+HCl

Chemical Etching Formula
1J79 Permalloy with FeCl₃+HCl

The FeCl₃+HCl chemistry is a proven formula for 1J79 Permalloy. This reference sheet lists the concentration (44 °Bé), specific gravity (1.410), bath temperature (50°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+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
0.04 mm Typical Thickness
0.19-66.68 m/min Conveyor Speed Range
4.37 m/min Typical Speed
8-360 μm Min Hole Ø Range
100-300 μm Min Line Width Range
1-54 μm Undercut Range
2.77 Etch Factor (EF)
97.0% Typical Yield (96.2-97.1%)

Why FeCl₃+HCl for 1J79 Permalloy?

On 1J79 Permalloy, 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 1J79 Permalloy 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 0.19-66.68 m/min — thinner sheets move faster, thicker sheets slower, in roughly inverse proportion to thickness. A typical mid-range setpoint is 4.37 m/min for 0.04 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

Feature sizes scale with sheet thickness. For this formula the minimum hole diameter ranges 8-360 μm and the minimum line width ranges 100-300 μm across the 0.01-0.3 mm band, following the industry 1.2× (hole) and 1.0× (line) thickness rules. Single-side undercut ranges 1-54 μm, and the etch factor is about 2.77. Size your photomask by subtracting twice the expected undercut from each finished feature dimension.

Design Rule Summary
• Minimum hole diameter range: 8-360 μm
• Minimum line width range: 100-300 μm
• Single-side undercut range: 1-54 μm
• Typical etch factor (EF): 2.77

Yield & Production Economics

Typical mass-production yield for 1J79 Permalloy in the FeCl₃+HCl system is 97.0%, within an observed range of 96.2-97.1%. 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

Parts produced with the FeCl₃+HCl formula on 1J79 Permalloy are common in hermetic sealing rings, lead frames matched to glass/ceramic, and magnetic shielding. The burr-free, stress-free nature of chemical etching makes it the preferred process wherever flatness and edge quality matter more than raw throughput.

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) 1J85 Super-Permalloy FeCl₃+HCl Through etch (double-sided) HyMu80 (Permalloy) FeCl₃+HCl Through etch (double-sided) Invar36 alloy FeCl₃+HCl Through etch (double-sided)

Frequently Asked Questions

Minimum producible hole diameter ranges 8-360 μm across the 0.01-0.3 mm thickness band, following the 1.2× material-thickness design rule. The smallest holes are only available on the thinnest stock; attempting holes below the floor for a given thickness causes yield to drop sharply.

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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