Chemical Etching Formula
Hastelloy C-22 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 Hastelloy C-22?

On Hastelloy C-22, 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 Hastelloy C-22 etch line runs a variant of this formula.

Process Window & Bath Control

Hold the bath at 56°C with concentration 48 °Bé (specific gravity 1.450). Across the 0.1-0.3 mm thickness range, conveyor speed runs from 0.12-0.6 m/min — thinner sheets move faster, thicker sheets slower, in roughly inverse proportion to thickness. A typical mid-range setpoint is 0.20 m/min for 0.20 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 120-360 μm and the minimum line width ranges 100-300 μm across the 0.1-0.3 mm band, following the industry 1.2× (hole) and 1.0× (line) thickness rules. Single-side undercut ranges 21-63 μm, and the etch factor is about 2.38. Size your photomask by subtracting twice the expected undercut from each finished feature dimension.

Yield & Production Economics

This formula delivers a typical yield of 94.2% (range 93.9-94.5%). At that rate, per-part economics are driven mostly by fixed photomask and setup cost for small batches and by sheet utilisation for large runs. The chemistry itself does not change with quantity, so the same recipe serves prototype and production volumes.

Typical Applications

Hastelloy C-22 etched with this recipe typically ends up in turbine-engine seals, high-temperature gaskets, and aerospace fluidic plates. 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

Production of Hastelloy C-22 parts using the FeCl₃+HCl formula described above runs on a wet chemical etching machine configured for through etch (double-sided). The bath chemistry, conveyor speed, and rinse cascade detailed on this page reflect the operating profile we use on a live spray-etching line for this alloy.

For a broader treatment of the material itself — alloy variants, surface preparation, and process limits across thickness ranges — see our Nickel chemical etching guide. That overview complements the formula-specific bath and conveyor data on this page.

Production Use Cases for This Formula

Production examples for the Hastelloy C-22 / FeCl₃+HCl recipe span high-speed air-intake mesh for hair dryers, stainless steel mesh for aroma diffusers, and tea-infuser custom filter etching. In every case, the etch factor and undercut figures on this page are the dominant tolerance drivers — bath maintenance discipline matters more than equipment headline rating.

Designs that sit slightly outside this thickness or feature-size envelope are usually addressable by a sister formula in the same etchant family. The bath chemistry stays the same; the tuning shifts to conveyor speed and resist choice.

Other Metals Etched with FeCl₃+HCl

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

More Nickel Superalloys Formulas

Other formulas in the same material family.

Frequently Asked Questions