The temperature of a substrate, while the covering is drawing on it’s surface, страница 40

Thermal electric transducers are produced according to main parameters resulted in tab. 12.1.

Thermal electric transducers and limits of admitted basic error should correspond [11]. Nominal static characteristics of standard thermal electric transducers transformation at temperature of the free ends 0˚С are resulted in [11].

Constructive manufacturing of thermal electric transducers is determined by conditions of their application. Thermoelectrodes are connected, as a rule, by welding or soldering with silver or tin solder. This connection formes the hot junction of the thermal electric transducer. Thermoelectrodes along the rest of length are isolated from each other. At low temperatures (up to 100-150˚С) application of any isolation (enamel, varnish, etc.) is possible. At higher temperatures tubes or beads from porcelain are used. Tubes and beads from oxide of aluminium, oxide of magnesium, oxide of beryllium, dioxides of thorium and dioxide of zirconium are used at temperatures more than 1300˚С.

Table 12.1 Basic parameters of thermal electric transducers

12.2 Choice of method of carrying out of measurements

The elementary gauge of a heat flow can be a metal disk temperature of which is controlled and which is in thermal balance with an environment.

To determine the heat-flow coming on the gauge, established in technological compartment of IPTI, it is necessary to limit a heat transfer from a disk except one mechanism - radiation. In conditions of technological compartment of ion-plasma technological installation with using as a technological source magnetron sputtering system the heat transfer due to convection isn’t realized because of low pressure of gases, and the heat transfer due to heat conductivity in a technological compartment can be reduced to a minimum due to the organization of experiment conditions.

In this case the heat flow, coming on a disk surface q_fall, after the reaching of thermal balance will be came up with the heat flow leaving the surface of the same disk q_rad.

q_fall = q_rad                                            (12.2)

And

q_rad =ε₀σТ_s⁴,                                        (12.3)

where ε– emissitivity factor;

σ- Stephan-Boatsman constant;

Т_s– temperature of a disk surface.

The balance of heat flows will be established on the disk surfaces

Q_fall = Q_rad,                                         (12.4)

where

Q_fall = q_fall ·S_D       ,                                      (12.5)

Q_rad,= q_rad · S_D      = q_rad ·ε₀σТ_s⁴         .         (12.6)

Then the heat flow, coming on the disk surface will be equal

q_fall =ε₀σТ_s⁴.                                                 (12.7)

12.3 Conditions of carrying out of measurements

Measurements are carried out at the following assumptions:

1)  Neglect non-uniformity of the heat flow _qпад, coming on the disk surface, owing to the small sizes of the disk and its small thickness.