| 摘要 |
FIELD: spark plugs. ^ SUBSTANCE: proposed spark plug has metal body and insulator embedded therein. Insulator accommodates pin-type internal current-conducting structure that has central electrode pin, current-limiting resistor, and central electrode sealed within insulator by means of heat-resistant sealing compound. The latter mainly has at least one metal component and also at least one ceramic component characterized in low coefficient of thermal expansion. Melting point of metal component is higher than operating temperature of spark plug and is below 1000 °C. Metal component is tin, bronze, active solder, or mixture thereof. Ceramic component is mullite, sillimanite, AlN, Si3N4, vitreous silica, or mixture thereof. Content of metal component is 20 to 40 volume percent and that of ceramic component, 60 to 80 volume percent. Provision is made for controlling coefficient of thermal expansion of sealing compound by varying proportion of its metal and ceramic components. ^ EFFECT: enhanced critical heat load sustained by sealing compound of spark plug. ^ 7 cl, 3 dwg
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