Patent ID: 6166481
Filing Date: 2000-12-26
Classification: H01T

Abstract:
A spark plug (100) comprising:a ground electrode (125);a firing electrode (115);an insulator core (105) having an insulator core nose (120); andan outer shell (110) surrounding the insulator core (105), wherein the improvement comprises the insulator core nose (120) including a high temperature glaze applied to an outer surface of the insulator core nose (120) and the high temperature glaze comprising, by weight:(i) between about 72 and 84% SiO.sub.2 ;(ii) between about 10 and 20% Al.sub.2 O.sub.3 ;(iii) between about 2.0 and 2.5% K.sub.2 O;(iv) between about 0.50 and 0.65% Na.sub.2 O;(v) between about 3.0 and 5.5% CaO;(vi) between about 0.1 and 0.25% MgO; and(vii) the remainder impurities.