Spark-plug composition

Studies of the formation, chemical composition, and properties of deposits have shown that they consist of partially oxidized organic material, including more or less nitrogen, sulfur, and phosphorus. Compounds of iron, silicon, calcium, and other metals are present in small quantity, together with substantial amounts of lead oxides, sulfates, and halides from combustion of the antiknock fluid. The effects of these deposits are both physical and chemical in nature they may physically interfere with lubrication, heat transfer, gas flow, operation of valves and spark plugs chemically, they may bring about corrosion and oxidation. 

The degree of distinction from a prior composition required to be patentable in part varies with the purposes. Where the closest prior art involved a corrosion inhibitor and a new additive to gasoline was to prevent spark plug fouling (44), the court held ... 

Phosphoric acid or aluminium add phosphates can be used to bond asbestos sheets [42], glass wool [43], vermiculite [44], fly ash [45], mica [46] or perlite [47] to make building materials or electrically insulating compositions. Phosphoric acid and caldum aluminate can be combined to produce a strong cement for sparking plugs [48]. 

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