Mu-Metal Etchants

Mu-metal is a nickel-iron alloy with very high magnetic permeability, making it highly effective at shielding against magnetic fields. Chemical etching of mu-metal is a process used to create precise patterns and shapes in this material, often for the purpose of manufacturing shielding components and devices. Here’s a guide on commonly used methods for etching mu-metal and how to set important parameters for effective mu-metal etching:

Commonly Used Mu-Metal Etchants

  1. Ferric Chloride (FeCl3)


  • Magnetic Shielding: Mu-metal is used to create shields that protect sensitive electronic equipment from external magnetic interference. Etching may be employed for shaping these shields.
  • Research and Development: In scientific and research applications, mu-metal components may undergo etching for custom designs and experimental setups.

Setting Parameters:

  • Temperature: Mu-metal etching with ferric chloride is typically performed at temperatures ranging from 35°C to 45°C (95°F to 113°F).
  • Concentration: A common concentration is around 40-45% ferric chloride in water. Ensure thorough mixing for consistent results.
  • Etching Time: The etching time can vary based on the depth and complexity of the design but often falls within the range of 5-30 minutes.
  • Agitation: Utilize an agitation mechanism within the etching equipment to maintain even etching and prevent the accumulation of byproducts.

Setting Parameters in a Mu-Metal Etching Operation

For an effective mu-metal etching operation using ferric chloride as an example:


  • Confirm and set the etching machine’s temperature control settings within the specified range of 35°C to 45°C.


  • Measure the required amount of ferric chloride accurately and mix it with water to achieve the desired concentration (e.g., 40-45%). Use calibrated instruments for precision.

Etching Time:

  • Determine the appropriate etching time based on the depth and complexity of the mu-metal design. Start with a shorter time and adjust as needed. Typically, a 10-15 minute initial test run is a good starting point.


  • Ensure that the etching equipment is equipped with an agitation system to maintain proper mixing of the ferric chloride solution throughout the etching process.


  • Prioritize safety by wearing appropriate personal protective equipment (PPE) such as gloves, safety goggles, and lab coats. Maintain a well-ventilated workspace with safety showers and eyewash stations.

Waste Disposal:

  • Dispose of used etchant solutions following local regulations, as ferric chloride is often considered hazardous waste. Proper handling and disposal are essential.

If you have an Mu-Metal etching project that you need help with, please contact us