Thermocouple to the hot electrode material requirements?

Hot electrode is thermocouple is an important element, how hot electrode material will directly affect the performance and precision of the thermocouple, in general, hot electrode should meet the following requirements: (as far as possible 1) Within the scope of the hot electrode measurement should be stable physical and chemical properties and pyroelectric properties; （ 2) The sensitivity of toxic dog and higher heat rate; （ 3) The relationship between thermoelectric potential and temperature best linear or simple function relationship, so that the measuring instrument of dividing work; （ 4) Good copy, same composition hot electrode thermoelectric properties should be basically the same; （ 5) Temperature coefficient of resistance and the specific heat, conductivity, to reduce the additional error in the measurement; （ 6) Better mechanical properties, have a certain strength and toughness, so that the hot electrode manufacturing to improve its service life; （ 7) As far as possible choose resources are abundant, cheap hot electrode.