Dilatometer.pptx

Dilatometer working and applications

1. The Basics of Dilatometer Theory and Data Analysis 1

2. Contents 2

3. 3 Thermal E xpansion & Thermal E xpansion C oefficient

4. Thermal Expansion - Background Thermal Expansion Background Most materials undergo dimensional changes during heating or cooling. Generally, the dimensions of a solid or liquid increase during heating and decrease during cooling. There are only few exceptions. Sintering, Shrinkage During phase transitions or during a sintering process, substances can show a shrinkage. During a sintering process, such shrinkages steps are irreversible and lead to a permanent increase in density and robustness. 4

5. Thermal Expansion - Background 5

6. W orking Principle Dilatometers work based on the principle of measuring changes in length or volume of a sample as temperature is varied. Common types of dilatometers include: Pushrod dilatometer Optical dilatometer Capacitive dilatometer 6

7. What is Dilatometry? Dilatometry (DIL) is a technique in which a dimensional change of a substance under negligible load is measured (e.g. expansion measurement or shrinkage measurement) as a function of temperature while the substance is subjected to a controlled temperature program in a specified atmosphere. 7

8. Equipment Setup 8

9. 9 Dilatometer Overview : -263 ℃ up to 2800 ℃

10. 10 Measuring System for DIL

11. Sample Carrier 11

12. Accessories for Dilatometry 12

13. 13 Furnace Program for DIL

14. Dilatometry Samples 14

15. Dilatometry Technical Specification Sample length: 20 mm maximum Maximum sample diameter: 7 mm Maximum change of length: 4 mm Length resolution: 10 nm 15 Sample holder: Fused silica Atmosphere: air, vacuum, Liquid nitrogen Temperature range: 100 – 1000°C Maximum heating rate: 100°C/min

16. Applications 16

17. Calibrations Used in Dilatometer 17

18. Interpretation of Dilatometer Graph Axis Labels   Baseline Expansion and Shrinkage   Slope   Inflection Points   Plateaus Peaks and Troughs Transition Temperatures Comparisons   Data Analysis 18

19. Axis Labels: The x-axis represents temperature, the y-axis represents the dimensional change   Baseline : Identify the baseline or initial position of the graph. This represents the starting dimensions of the sample at the initial temperature. Expansion and Shrinkage: Upward curves indicate expansion, while downward curves indicate shrinkage of the sample.   Slope : R epresents the rate of dimensional change with temperature. Steeper slopes indicate higher rates of expansion or shrinkage.   Inflection Points: Identify any significant changes in the slope or curvature of the graph. These points indicate phase transitions, where the material undergoes structural changes.   Plateaus : Look for regions of the graph where the dimensions remain relatively constant. These plateaus may indicate a stable phase or minimal dimensional change within a specific temperature range. Peaks and Troughs: Peaks indicate maximum expansion or dimensional change, while troughs represent maximum shrinkage. Transition Temperatures: Determine the temperatures corresponding to significant changes in the graph, such as phase transitions or other critical points. These temperatures provide valuable information about the material's behavior . Comparisons : Compare the graph of the tested sample with known reference materials or expected behavior . This allows for further analysis and understanding of the material's characteristics.   Data Analysis: Quantitatively analyze the graph to calculate coefficients of thermal expansion (CTE) or other relevant parameters, depending on the specific purpose of the experiment. 19

20. 20 Thermal Expansion Coefficient of LaCrO3

21. Determination of the Glass Transition 21

22. Glass Transition of Polymer Comparison TMA and DSC 22

23. 23 Glass — Thermal Expansion, Glass Transition, Softening Presented in the figure are three tests on the same type of glass but from different batches. It can clearly be seen that the coefficients of thermal expansion are in good agreement within the instrument’s uncertainty boundaries. The  Glass Transition Temperature  temperature and the softening point of sample #3 (blue curve) show slightly lower values, indicating a slightly different composition .

24. Ceramic Sintering 24

25. Sintering of Clay 25

26. Thin Film- Epoxy Film on Glass Substrate 26

27. Phase Transition-Steel 27

28. 28 Iron – Phase Transition The sample was measured at a heating rate of 5 K/min in a helium atmosphere. At 906°C (peak temperature in the physical alpha) a shrinkage step was detected. This is due to a change in the lattice structure (bcc -> fcc ). Another change in the lattice structure ( fcc -> bcc) was detected at 1409°C. The deviation between the measured and literature transition temperatures is due to a small impurity content.

29. 29 Phase Transition-SiO2

30. 30 Phase Transition-SiO2

31. 31 Density Change – Powders & Melts

32. 32

33. 33 Optimization of Casting Process