| 摘要 |
PURPOSE:To improve moisture resistance and to obtain a sensor having stable and good responsiveness by depositing borate of an alkaline earth metal (Be, Mg, Ca, Sr, Ba) on a semiconductor essentially consisting of tin oxide. CONSTITUTION:Aq. soln. of the nitrate of one kind of the alkaline earth metal selected from Be, Mg, Ca, Sr, and Ba and of boric acid is mixed with a sintered body of a tin oxide semiconductor to prepare the soln. The porous tin oxide semiconductor is immersed into such soln. and is dried; thereafter, a coil 1 is again energized to heat the semiconductor and to thermally decompose the nitrate. The nitrate is thereby decomposed and the earth metal is converted to oxide. The semiconductor part 6 of the gas sensor 5 in which the fine particles 3 of said oxide are deposited on the surface of the tin oxide is thus formed. The moisture resistance is thereby improved and the sensor having the stable and good responsiveness is obtd.
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