Sensor utilizing thermoelectric material and method for manufacture thereof

A sensor for measuring gas pressure and density of a specific substance comprising:

• a pellet of powder thermoelectric material having a fine structure in which fine particles of one compound exhibiting a Seebeck effect are made by a cold pressing and are electrically linked in a state of loose contact with one another without fusing so as to exhibit said effect, having spaces formed at clearances between the fine particles;
• means for generating a temperature difference between two points inside said pellet of the thermoelectric material;
• and
• means for sensing a thermal electromotive force generated between the two points inside said pellet;
• and wherein said fine particles of the thermoelectric material are coated with a material having a specificity of adsorption of the specific substance.

A method of manufacturing a sensor for quantitatively detecting a specific substance in an atmospheric gas comprising the steps of:

• a. producing a powder thermoelectric material having a composition of Fe.sub.0.985 Mn.sub.0.015 Si.sub.2 by a method comprising:
• i. compacting fine particles made of one compound exhibiting a Seebeck effect, said compacting consisting essentially of a cold pressing to produce a thermoelectric material composed of fine particles loosely contacting each other so as to exhibit said effect, with spaces formed at clearances between the particles, and before said cold pressing, the steps of melting specified amounts of raw materials of Fe, Mn and Si, each having a purity of not less than 99.9% in an arc furnace and then crushing;
• ii. repeating the cycle of melting/crushing;
• iii. analyzing the composition of the resultant material;
• and
• iv. then adjusting the ratio of the raw materials to derive a composition of Fe.sub.0.985 Mn.sub.0.015 Si.sub.2 ;
• and
• b. processing the resultant powder thermoelectric material into granules each having a size of 5 to 10 .mu.m in diameter;
• c. mixing formaldehyde dehydrogenase enzyme serving as a material having a specificity of adsorption into polyacrylamide sol and mixing the resultant mixture with the powder thermoelectric material of Fe.sub.0.985 Mn.sub.0.015 Si.sub.2, thereby to obtain a slurry;
• d. atomizing the mixed slurry in a dried Ar gas atmosphere thereby to gelatinize the polyacrylamide sol, dispersing excessive solvent by evaporation;
• and
• e. dispersing the obtained powder material in an organic solvent to be formed on a glass substrate through printing.