Chemical Etching Formula
HyMu80 (Permalloy)
with FeCl₃+HCl
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.
Why FeCl₃+HCl for HyMu80 (Permalloy)?
Ferric-chloride-based formulas are the industrial workhorse for ferrous, nickel, and copper-bearing alloys like HyMu80 (Permalloy). The Fe³⁺ ion oxidizes the metal surface; where HCl is present it regenerates dissolved species and stabilizes chloride concentration. The result on HyMu80 (Permalloy) is anisotropic etching with predictable undercut and an easily regenerated spent bath.
Process Window & Bath Control
The process window for this FeCl₃+HCl formula centres on 50°C and 44 °Bé. Conveyor speed spans 0.34-2.69 m/min over the 0.05-0.2 mm thickness band; the typical operating point is 0.95 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
Design rules for this recipe: hole diameter 60-240 μm, line width 100-200 μm, single-side undercut 9-36 μm — all as a function of thickness across 0.05-0.2 mm. The higher the etch factor (this formula holds about 2.75), the tighter the achievable tolerance. Below the minimum feature sizes, yield falls off steeply, so treat those numbers as hard floors rather than targets.
• Minimum hole diameter range: 60-240 μm
• Minimum line width range: 100-200 μm
• Single-side undercut range: 9-36 μm
• Typical etch factor (EF): 2.75
Yield & Production Economics
Expect a yield in the 96.4-96.8% range for HyMu80 (Permalloy) with FeCl₃+HCl, with 96.7% 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
HyMu80 (Permalloy) 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.
Frequently Asked Questions
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.