The spectral emissivity of an oxide film of zirconium for wavelengths of $530$ and $650$ nm in the temperature range from $1450$ to $1750$ K

The pyrometer method is used to investigate the spectral emissivity of an oxide film of zirconium of a nonstoichiometric composition in the temperature range from $1450$ to $1750$ K for wavelengths of $530$ and $650$ nm. The obtained data are used to calculate the color temperature. The results relate to a tetragonal structure of zirconium oxide in the range from $1450$ to $1730$ K and to a mixture of tetragonal and cubic structures at $1745$ K. The sample to be investigated is heated in a high-frequency field of a multiturn cylindrical inductor in an air/argon mixture in a hermetically sealed volume with a volume content of air of $6.2\%$. The oxide film thickness, estimated by the increment of the sample mass, ranges from $124$ to $613\mu$m. The estimated error of measurement of the coefficients of spectral emissivity is $10\%$.