CONSIDERATIONS ON THE ADSORBED WATER CONCENTRATION OF SULFURIC POROUSALUMINUM-OXIDE

To understand the mechanism determining the over long response time of porous alumina humidity sensors, the study of the interaction between water and the anodic alumina was begun by determining the adsorbed wa ter concentration at room temperature and pressure of the most utilize d alumina-the sulfuric porous anodic alumina. The adsorbed water conce ntration in a dissociated state can be estimated as 100 OH nm-2, a con stant value in a large domain of preparation conditions: 8.4-27 wt.% s ulfuric acid concentration, +10 to -15-degrees-C, and 40-400 A m-2 ano dic current density.