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.

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.

Process Equipment & Material Reference

Process equipment for the HyMu80 (Permalloy) / FeCl₃+HCl combination is built around our wet chemical etching machine platform — closed-loop temperature control, redundant pump headers, and metering for bath replenishment all directly affect the etch factor and yield numbers cited on this page.

The material above is documented on this page at the recipe level. Bath chemistry, temperature, and conveyor speed are the controlling variables for repeatable output.

Production Use Cases for This Formula

Parts produced with this HyMu80 (Permalloy) + FeCl₃+HCl formula end up in a wide range of finished products. Representative production runs we have completed using this exact recipe family include soy-milk-maker filtration mesh, stainless steel metal filter mesh, and high-speed air-intake mesh for hair dryers. Each case shares the same root sensitivity: clean photoresist edges, a tightly held bath SG of 1.410, and a conveyor speed inside the 0.34-2.69 m/min envelope.

If your part falls into one of these classes — or a closely adjacent one — this formula is usually the right starting point. We confirm fit with a short sample run on the actual sheet stock before locking in mask artwork.

Other Metals Etched with FeCl₃+HCl

The FeCl₃+HCl chemistry is also documented for these alloys.

More Precision Alloys Formulas

Other formulas in the same material family.

Frequently Asked Questions