High fire multilayer ceramic capacitor electrode technology

Palladium and palladium-silver multilayer ceramic capacitor (MLC) electrodes for high fire systems have fundamentally different technology versus that for low fire system. Pd oxidation to PdO is a primary consideration. The phase diagram for the system Pd-Ag-O is used to demonstrate and quantify the effect of Ag on Pd oxidation. Choice of Pd powder is important for oxidation resistance. Additives can also control Pd oxidation. Pd sintering occurs essentially below 900°C, just above the temperature at which PdO reduces back to the metal. Additives can also control Pd sintering and make the temperature range over which Pd densifies more closely match that of high fire dielectrics. Control of Pd oxidation and sintering shrinkage mismatch with dielectrics is important in connection with avoiding physical defects in finished MLC parts