Black Body Radiation Cavity for Sapphire High Temperature Fiber Optic Sensor

Abstract

The invention belongs to the optical detection technology and relates to a black-body radiation cavity for a sapphire high-temperature fiber-optic sensor. Both the outer surface and one end face of a sapphire optical fiber are provided with even film layers, the end face of the sapphire optical fiber is completely covered with the corresponding film layer, a cylindrical black-body radiation cavity is formed outside the sapphire optical fiber and made from mixture of zirconia and yttrium oxide in a weight ratio of 20:1-5:1, and the film layers are 0.5-5 micrometers in thickness. The black-body radiation cavity is made from the mixture of zirconia and the yttrium oxide and has the effect of preventing the film layers from cracking and shedding at the high temperature of 1700-1850DEG C, so that temperature measurement range of the sapphire high-temperature fiber-optic sensor is widened greatly.

Description

technical field [0001] The invention belongs to the optical detection technology and relates to a blackbody radiation cavity used for a sapphire high-temperature optical fiber sensor. Background technique [0002] The black body radiation cavity is the thermal sensitive element in the sapphire high temperature fiber optic sensor, which converts the thermal signal of the measured environment into an optical signal, and the temperature of the measured environment can be obtained by analyzing the size of the optical signal. Since the blackbody radiation cavity is directly in contact with the high-temperature environment to be measured, the requirements for the firmness of the blackbody cavity coating on the sapphire optical fiber are very high. The existing sapphire high-temperature optical fiber sensor blackbody radiation chamber film material uses zirconia material, because the thermal expansion coefficient of zirconia does not completely match that of the sapphire optical fi...

AI Technical Summary

Problems solved by technology

The existing sapphire high-temperature optical fiber sensor blackbody radiation chamber film material uses zirconia material, because the thermal expansion coefficient of zirconia does not completely match that of the sapphire optical fiber, in practical applications, the higher the measured ambient temperature, the more zirconia film layer It is easy to fall off, which seriously affects the temperature measurement performance of the sapphire high temperature optical fiber sensor

In addition, the existing sapphire high-temperature optical fiber sensor blackbody radiation cavity is made by high-temperature sintering method. Due to the limitation of process conditions, the film thickness of the blackbody radiation cavity is as high as 100 μm, which greatly reduces the thickness of the blackbody radiation cavity film. Robustness of layers on sapphire fiber

[0003] To sum up, the existing sapphire high-temperature optical fiber sensor black body radiation cavity has two shortcomings: 1) The thermal expansion coefficient of the coating material does not completely match the thermal expansion coefficient of the sapphire optical fiber; 2) The coating is too thick

The above two factors make the film layer of the existing sapphire high-temperature optical fiber sensor blackbody radiation cavity easy to crack and even fall off seriously under high temperature conditions above 1700°C, resulting in unstable performance of the sapphire high-temperature optical fiber sensor, and it is difficult to operate in a high-temperature environment above 1700°C normal work

Images