Wire Mesh for EMI Shielding: Copper,

https://www.hrmeshs.com/news/wire-mesh-for-emi-shielding-copper-brass-and-nickel-mesh-compared.html

When you source wire mesh for EMI shielding, selecting the correct metal is just as important as selecting the mesh count, wire diameter, opening size, and installation method. Copper, brass, and nickel mesh can all reduce electromagnetic interference, but they do not provide identical electrical conductivity, magnetic response, corrosion resistance, mechanical strength, or processing performance.

Copper mesh is generally your first option when high electrical conductivity and strong radio-frequency shielding are the main requirements. Brass mesh provides a practical balance between conductivity, mechanical strength, dimensional stability, and procurement cost. Nickel mesh is more suitable when your shielding component must also withstand alkaline media, elevated temperatures, repeated handling, or specific magnetic-field conditions.

You should not select wire mesh for EMI shielding from the material name alone. The required frequency range, shielding target in decibels, enclosure structure, grounding method, operating environment, and contact with adjacent metals all affect the final result.