INSULATING MATERIAL FOR SPARK PLUG, ITS PRODUCTION AND SPARK PLUG USING THE SAME

摘要

PROBLEM TO BE SOLVED: To obtain both an insulating material for spark plug high voltage endurance characteristics at a high temperature in the vicinity of 700 deg.C and a spark plug provided with the insulating material. SOLUTION: This insulating material 2 for a spark plug comprises alumina (Al2O3) to be used for a spark plug 100 as a main component is constituted of an alumina base sintered compact which contains at least a silicon(Si) component and one or more rare earth elements (RE for short) and has >=95% theoretical density ratio. The insulating material 2 for a spark plug has an insulating material controlling the occurrence of dielectric breakdown affected by residual pores existing at an alumina crystal grain boundary and a low-melting glass phase and having excellent voltage endurance characteristics at a high temperature of about 700 deg.C by the constitution.