Varistors and LTCCs were immersed in three different baths: nickel sulfamate, citric acid, and Melbrite NI-2226, for 5 hours at 45°C. The weight loss was lowest when immersed in NI-2226 and highest in the citric acid bath.
In Melbright NI-2260, the concentration of nickel is very low after wastewater treatment. It is same level as the case of sulfamate nickel bath. While a citric bath is difficult to treat wastewater.