Thermo-optic Refractometry for High-Temperature Ceramic Samples
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Solution Overview
Problem
Current refractometers are limited to measuring the refractive index of materials under relatively low-temperature conditions, typically below 1000°C, and lack the capability to account for thermal expansion, which restricts the characterization of materials at higher temperatures.
Innovation Solution
A method and apparatus that utilize a thermal control mechanism, thermal expansion compensation, and rotation mechanism to securely hold and measure the refractive index of materials at elevated temperatures up to 1500°C, incorporating a sample holder made from refractory metals and employing visible and infrared lasers to determine the refractive index under varying thermal conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional refractometers are used to measure refractive index, then measurement can be performed under low-temperature conditions, but the device cannot measure materials at high temperatures above 1000°C
Solution Approach 1:
The patent changes the physical parameters of the sample holder by using refractory metals (tungsten, molybdenum, niobium) that can withstand high temperatures up to 1000°C and above. This material parameter change enables the measurement system to operate at elevated temperatures while maintaining structural integrity and measurement accuracy.
2Measurement precision
If thermal expansion is not compensated for, then the device structure remains simple, but measurement accuracy deteriorates due to thermal expansion effects at high temperatures
Solution Approach 1:
The patent explicitly addresses thermal expansion by using sample holder materials (refractory metals) with known and stable thermal expansion characteristics. The system compensates for thermal expansion effects through careful selection of materials and design of the sample holder geometry, enabling accurate refractive index measurements at high temperatures where thermal expansion would otherwise cause significant measurement errors.
3Reliability
If secure holding of material sample at high temperature is required, then thermal control and stabilization mechanisms are needed, but the device complexity increases
Solution Approach 1:
The patent employs refractory metal sample holders that inherently provide thermal stability and structural integrity at high temperatures without requiring complex active control systems. The materials themselves serve the function of maintaining sample positioning and withstanding thermal conditions, reducing the need for additional complexity in thermal control mechanisms while ensuring reliable measurement conditions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables accurate and repeatable measurement of refractive indices for high-temperature optically transparent ceramic materials, providing multispectral characterization and accounting for thermal expansion, thus overcoming the limitations of existing refractometers.
Implementation Method 1
The thermal control mechanism may include a thermal controller coupled to an induction coil apparatus and a temperature sensor
Implementation Method 2
projecting a laser beam into the material sample... collecting a refracted laser beam from the material sample
Implementation Method 3
a thermal expansion compensation mechanism... holds the material sample reliably and securely regardless of thermal expansion of the material sample and the device
Data Source
AI summary
A method of determining a refractive index of a material sample comprises removably mounting the material sample into a sample holder having a thermal control mechanism, a thermal expansion compensation mechanism, and a rotation mechanism; projecting a laser beam into the material sample, wherein the material sample has a predetermined orientation and temperature, wherein the material sample has parallel sides defining parallel planes for entry and exit of the laser beam into and out of the material sample; collecting a refracted laser beam from the material sample, and determining the refractive index for the material sample at the predetermined temperature. The laser beam may be a visible laser and/or an infrared laser. The thermal control mechanism comprises a thermal controller coupled to an induction coil apparatus and a temperature sensor. The sample holder comprises a refractory metal consisting of one or more of a niobium/molybdenum alloy and a tantalum/tungsten alloy.