Abstract: An alloy useful for producing massive spark plug center electrodes is disclosed. The alloy consists essentially of from 0.9 to 1.5 percent of ruthenium, from 0.9 to 1.5 percent of manganese, and from 97 to 98.2 percent of nickel. Preferably, the alloy additionally contains 1 percent of silicon. The optimum alloy consists essentially of substantially 1 percent of each of Ru, Mn, and Si, balance Ni.

Abstract: A silicon-talc sealing material is disclosed. The sealing material is made up of about 15 to 30 percent by weight of silicon metal powder and about 85 to 70 percent by weight of talc. It has been found to be admirably suitable for sealing around the center wire of spark plugs in which the sealing material is subjected to temperatures of about 900.degree. F. or higher. In such applications, the sealing material is unexpectedly advantageous by comparison with previously known materials, because it has significantly higher holding power, because it allows significantly less gas leakage, or because it has both advantages.