| 摘要 |
PURPOSE:To obtain a detection element material having high detection sensitivity and capable of detecting the presence of carbon dioxide at low temp., by using a composite material consisting of hydroapatite represented by a specific formula and inorg. carbonate. CONSTITUTION:A powder of hydroapatite represented by formula M10(ZO4)6(OH)2 (wherein M is an element selected from a group consisting of calcium, barium, strontium, lead and cadmium and Z is an element selected from a group consisting of phosphorus, arsenic and vanadium) is subjected to compression molding and an obtained compact is pref. heated at 850-950 deg.C for 1.5-2.5hr in an electric furnace to obtain a porous sintered body comprising hydroapatite. This sintered body is immersed in an aqueous solution of inorg. carbonate (pref., sodium carbonate or calcium carbonate) and dried to adhere inorg. carbonate to the surface of hydroapatite to obtain a hydroapatite-inorg. carbonate composite 1. Electrodes 2 for measuring electric resistance or impedance and lead wires 3 are mounted to both sides of the composite 1 to obtain a detection element.
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