“Nickel silver is fast becoming the preferred alloy for the majority of board level shielding tasks according to Precision Micro, the Birmingham based precision metal components manufacturer. The material is said to be replacing traditional plated steel and yellow metals across the board and certainly for those applications above 15MHz where shielding effectiveness becomes more of a skin (conductivity) effect than a bulk effect. Nickel silver is less conductive than copper and brass but far stronger. Although this RoHS compliant material is marginally more expensive, it doesn’t need plating to improve its solderability or corrosion resistance, so invariably finished shielding cans manufactured in nickel silver are less expensive.” Source: electronicstalk.com