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Thermophysical Properties
- Lab E13)
  Laser Flash Thermal Diffusivity
A single 1-ms pulse of infrared laser light strikes the front of cylindrical sample while the back face is monitored with a infrared detector. The temperature rise curve is fit to a theoretical curve and the diffusivity is determined at several points on the curve. This is the standard measurement for thermal transport, including thermal conductivity, which is equal to the product of bulk density, thermal diffusivity, and the specific heat capacity. Thermal diffusivity may be measured between room temperature and 2000o C.
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  The sample is placed in the center of the tantalum tube furnace shown to the left. Measurements above room temperature are performed in an inert environment. The infrared laser is shown to the right. The light is diffused through a copper sulphate solution.Sample Size is 10 mm Diameter By 4 – 6 mm thickness.
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  Helium Pycnometry
A pycnometer is used to accurately determine the bulk volume as part of density determination. The system is filled with helium. The volume of each section of the system is known. The pressure is measured before and after a section at atmospheric pressure is added. The ideal gas law is used to determine the volume of a specimen.The mass is measured separately and combining the volume and mass information, we get the density, density = mass/volume. |
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 Thermogravimetric Analysis (TGA)
A specimen holder hangs on one arm of a precision microbalance to measure mass. A program is run in which the flowing gas environment is controlled and the furnace is heated at specified rates or held at constant temperature for specified periods. Using this technique, one can determine reaction temperatures and rates for the given environmental conditions. Measurements may be taken between room temperature and 1700o C. Samples are in the form of powders or solid pieces. |
|   Gas Mass Flow Controllers
In experiments where gas flow is used, it is important that there not be any pressure variations and that a constant flow is maintained. The mass flow valves are controlled by the remote unit shown on the left. This can be used with most common gases, such as: N, He, Ar, CO2, O2, air, etc. |
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 Dilatometry - Thermal Expansion Testing
This is a push rod-style dilatometer. The sample carrier and push rod are alumina. The rod pushes against one side of a small bar of the material to be tested. The opposite end is held by an alumina stop. The sample sits within a tube furnace with a maximum temperature of 1600o C and is tested under flowing inert gas. The high precision measuring head is water-cooled. The sample can be placed in a vacuum or an inert gas. The sample can be rectangular or cylindrical with a maximum diameter of 12 mm and a maximum length of 25 mm. |
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  Differential Scanning Calorimetry (DSC)
A differential scanning calorimeter (DSC) measures energy flow into (endothermic) or out of (exothermic) a specimen using a high sensitivity measuring head. The technique measures between room temperature and 1400o C under a flowing, inert gas the following properties: specific heat, melting temperatures, transition enthalpies, phase transformations, phase diagrams, crystallization temperatures, degree of crystallinity, glass transition temperatures, decomposition effects, reaction kinetics, and purity. Samples can be powder, small pieces, or up to 5 mm diameter disks with a thickness of 3 mm. Crucible materials are, graphite, platinum, or alumina. |
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 Analytical Balance
The balance is used for precise mass determination down to 0.00001g. It has been interfaced to a computer for experimental use, such as in density/open porosity determination using the mineral spirits method. Data-logging software allows the measurement of mass loss or gain per unit time. |
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