METHOD FOR DETERMINING EMISSIVITY OF HARD MATERIALS AND DEVICE FOR ITS IMPLEMENTATION Russian patent published in 2017 - IPC G01N25/20 G01J5/10 

FIELD: physics.

SUBSTANCE: unlike the conventional method for determining the emissivity of the solid materials, consisting in the fact that the sample is exposed to the laser radiation, the true contact temperature T of the sample surface is measured during exposure, the radiation intensity of the sample is simultaneously contactlessly determined, and the obtained data are used for determining the emissivity, in the inventive method the sample is exposed to the laser radiation transformed into thermal radiation, the brightness temperature T_я of the sample surface is measured after uniform heating the sample by the converted laser radiation in the studied spectral range of the thermal radiation wavelengths from the sample from λ₁ to λ₂ T_я, by which the thermal radiation intensity of the sample is judged. Herewith the brightness temperature T_я of the sample surface is measured simultaneously with the measurement of the true temperature T of the sample surface at the same point of the working sample surface heating zone. The calculation of the integral ε emissivity is carried out in the spectral range of the thermal radiation wavelengths of the sample from λ₁ to λ₂ by using the obtained inventive data with the following relation based on Planck's formula

,

where C₁=2πhc²=3,7413⋅10^-16 Bt⋅m², C₂=hc/k=1,4388⋅10^-2 m⋅K - first and the second radiation constants; λ - the length of the thermal radiation from the sample, T_я and T - the inventively obtained brightness and true temperatures of the sample surface, respectively, at the same time and at the same point of the sample surface. Also, the device is proposed for determining the emissivity of the solid materials, in which a transducer of the laser radiation into the thermal radiation - a thermal converter, is placed behind the laser radiation source with the optical circuit on its axis in front of the sample in direct contact therewith, that provides uniform heating of the sample in the working area. The converter and the sample are placed in a shielded thermal insulation box. An optical pyrometer, with the viewing area and a typical size not exceeding the size of the working area of the uniform sample heating, is mounted behind the sample on the axis of the laser radiation source as a radiation intensity measuring means from the sample.

EFFECT: improving the accuracy of determining thermal parameters.

2 cl, 2 dwg