Chemical Etching Formula
Inconel 625 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 Inconel 625?

On Inconel 625, 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 Inconel 625 etch line runs a variant of this formula.

Process Window & Bath Control

Hold the bath at 54°C with concentration 46 °Bé (specific gravity 1.430). Across the 0.01-0.5 mm thickness range, conveyor speed runs from 0.12-47.63 m/min — thinner sheets move faster, thicker sheets slower, in roughly inverse proportion to thickness. A typical mid-range setpoint is 0.70 m/min for 0.10 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 8-600 μm and the minimum line width ranges 100-500 μm across the 0.01-0.5 mm band, following the industry 1.2× (hole) and 1.0× (line) thickness rules. Single-side undercut ranges 1-101 μm, and the etch factor is about 2.48. Size your photomask by subtracting twice the expected undercut from each finished feature dimension.

Yield & Production Economics

This formula delivers a typical yield of 95.5% (range 94.3-95.8%). 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

Parts produced with the FeCl₃+HCl formula on Inconel 625 are common in turbine-engine seals, high-temperature gaskets, and aerospace fluidic plates. The burr-free, stress-free nature of chemical etching makes it the preferred process wherever flatness and edge quality matter more than raw throughput.

Process Equipment & Material Reference

Production of Inconel 625 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.

Related to this formula, the Nickel chemical etching guide page documents the full process envelope for the same alloy family, including pre-treatment chemistry and post-etch inspection criteria.

Production Use Cases for This Formula

Typical end-uses for Inconel 625 run on this formula include high-speed air-intake mesh for hair dryers, stainless steel mesh for aroma diffusers, and soy-milk-maker filtration mesh. The 54°C bath and 0.01-0.5 mm supported thickness range cover most of the production work in these segments without re-tuning chemistry.

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