Monitoring sensor for temp.-dependent wear and ageing - uses material, e.g. layers of zircon and nickel@, whose speed of ageing depends on temp. and is electrically measurable

摘要

The sensor includes a section having an electrically measurable material property (pref. electrical conductivity) which changes irreversibly at a rate dependent on temp. The sensor pref. has at least one pair of adjacent layers of different materials, one of which is capable of temp-dependent diffusion into the other to produce a permanent conductivity change in the diffusion zone. Pref. the materials are transition metals, esp. Zr and Ni, in the form of vapour deposited layers on a substrate or in the form of foils which are pref. wound into a coil. The layers are pref. at least 0.5 microns thick. The sensor part is pref. gas-impreviously encapsulated, esp. in a protective gas or vacuum. USE/ADVANTAGE - Components subjected to heavy thermal loading, e.g. motor vehicle clutch or brakes. Reliability achieved by using solid state amorphisation effect with inherent measurement storage requiring no external circuitry.