Abstract An essentially full range resistance type relative humidity sensing element is produced by providing a dielectric blank, on which an electrode system has been applied, with a metal oxide coating, in a manner which imparts a porous structure thereto, and subsequently chemically bonding chlorine covalently into the oxide to produce an oxychloride structure. The metal oxide used is selected from a group, including those of Group VIII, Period 4 of the Periodic Table, which exhibit electrical insulating properties, the amount of electrical resistance thereof being dependent on the relative humidity of the environment to which it is exposed. The sensing element thus produced exhibits a much lower total electrical resistance coupled with a narrower range of variation in resistance produced by changes in relative humidity whereby rendering it compatible with ordinary electrical resistance measuring devices.
A moisture sensitive element comprising spaced metal electrodes, an electrically insulating metal oxide coating overlapping said electrodes, said oxide having an electrical resistance which is humidity-dependent, said coating being of a porous nature, and wherein the said metal oxide coating contains chlorine covalently bonded therein, thereby imparting an oxychloride structure thereto, and electrical leads attached to said electrodes.
Claim 2
Dependent Claim
58 words
A moisture sensitive element comprising spaced metal electrodes, an electrically insulating metal oxide coating overlapping said electrodes, said oxide having an electrical resistance which is humidity-dependent, said coating being of a porous nature, and wherein the said metal oxide coating contains chlorine covalently bonded therein, thereby imparting an oxychloride structure thereto, and electrical leads attached to said electrodes.
Claim 3
Dependent Claim
27 words
A moisture sensitive element as claimed in claim 1, including a substantially inert dielectric blank member, and a noble metal electrode system applied to said blank member.
Claim 4
Dependent Claim
35 words
A moisture sensitive element as claimed in claim 1, wherein said metal oxide is one selected from the oxides of the elements contained in Group VIII, Period 4 of the Periodic Table of the Elements.
Claim 5
Dependent Claim
15 words
A moisture sensitive element as claimed in claim 2, wherein said metal oxide is Fe2O3.
Claim 6
Dependent Claim
17 words
A moisture sensitive element as claimed in claim 1, wherein said electrode system has an interdigital configuration.