A spark plug having a multilayer firing tip that minimizes the amount of
precious metal used and a method of assembling a spark plug with a
multilayer firing tip. The firing tip includes a discharge end and a weld
end, with the weld end being connected to a center electrode, and more
specifically to a base electrode on the center electrode. The weld end
has a coefficient of thermal expansion, which is not between the values
for the coefficients of thermal expansion for the discharge end and the
base electrode. More specifically, the weld end has a coefficient of
thermal expansion which is greater than the coefficients of thermal
expansion for the discharge end and base electrode. The weld end is
formed from Nickel and Chromium with a limited amount of additional
elements. The spark plug is assembled by providing a first elongated
material formed from the material used for the discharge end and a second
elongated material formed from a material used for the weld end. The two
materials are then joined to form a single joined material and are
severed to create a firing tip. The firing tip is welded to the center
electrode of the spark plug and more specifically, the base electrode.