Nickel Superalloys FeCl₃+HCl

Chemical Etching Formula
Hastelloy C-22 with FeCl₃+HCl

Working with Hastelloy C-22 on a chemical etch line begins with the right formula. The FeCl₃+HCl system documented below produces through etch (double-sided) across 0.1-0.3 mm sheet, with a minimum hole-diameter range of 120-360 μm and a minimum line-width range of 100-300 μm. The numbers scale with thickness — thinner stock yields finer features.

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
48 °Bé Concentration
1.450 Specific Gravity
56 °C Bath Temperature
Through etch (double-sided) Etch Depth Type
0.1-0.3 mm Thickness Range
0.20 mm Typical Thickness
0.12-0.6 m/min Conveyor Speed Range
0.20 m/min Typical Speed
120-360 μm Min Hole Ø Range
100-300 μm Min Line Width Range
21-63 μm Undercut Range
2.38 Etch Factor (EF)
94.2% Typical Yield (93.9-94.5%)

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.

Design Rule Summary
• Minimum hole diameter range: 120-360 μm
• Minimum line width range: 100-300 μm
• Single-side undercut range: 21-63 μm
• Typical etch factor (EF): 2.38

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.

More Nickel Superalloys Formulas

Other formulas in the same material family.

Hastelloy C-276 FeCl₃+HCl Through etch (double-sided) Hastelloy X FeCl₃+HCl Through etch (double-sided) Inconel 600 FeCl₃+HCl Through etch (double-sided) Inconel 601 FeCl₃+HCl Through etch (double-sided) Inconel 625 FeCl₃+HCl Through etch (double-sided) Inconel 690 FeCl₃+HCl Through etch (double-sided)

Frequently Asked Questions

Typical inspection on Hastelloy C-22 etched with FeCl₃+HCl includes optical checks for unetched residue and surface defects, dimensional metrology on critical features, and edge-quality assessment. Final dimensional tolerance is usually ±10% of the smallest critical feature or ±25 μm, whichever is larger.

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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