Thermal Dilatometric Analysis (TDA), often called "dilatometry", measures the dimensional change of a material (ceramics, glasses, metals, composites, carbon/graphite, minerals, polymers, and others) as a function of temperature. This test determines both reversible and irreversible changes in length (expansion and shrinkage) during heating and cooling, and pinpoints where reactions occur that cause expansion or contraction. The dilatometer is used to determine Coefficient of Thermal Expansion (CTE), softening point, glass transition temperature, curie point, crystalline transformation, phase transition, shrinkage, warping, bloating, sintering rate, isothermal creep, and stress relaxation. Samples are quickly and easily measured for determining firing ranges and firing schedules, measuring thermal expansion ranges for glaze fits, and measuring thermal expansion ranges for R&D, QC or product certification.

For Dilatometers in China, please contact Leadwin Instruments

Standard, Single Sample, Horizontal Dilatometers

Model	DIL 2010 B	DIL 2010 C	DIL 2010 STD	DIL 2012 STD	DIL 2016 STD
.
Temperature Range	RT to 1,000°C	RT to 1,000°C or -170°C to +500°C	RT to 1,000°C	RT to 1,200°C	RT to 1,600°C
Furnace	Kanthal Wire	Nichrome Wire or Cryogenic Chamber	Kanthal Wire	Kanthal Wire	Silicon Carbide
Thermocouple	Type N	Type N	Type S	Type S	Type S
Sample Holder and Probe Rod	Fused Quartz	Fused Quartz	Fused Quartz	High Alumina	High Alumina
Sample Size (max)	50 mm long by 20 mm diameter	50 mm long by 10 mm diameter	50 mm long by 20 mm diameter	50 mm long by 20 mm diameter	50 mm long by 20 mm diameter
LVDT Displacement Range	±0.100 inch (±2.54 mm)
Displacement Resolution1	0.0000009 inch or 0.9 micro-inch ( 0.00002 millimeter or 0.02 microns)
PLC Resolution for a 1" Sample1	0.00009%
Reproducibility Range1		± 0.004 PLC (± 1 μm / ± 40 μ-inches)	± 0.004 PLC (± 1 μm / ± 40 μ-inches)	± 0.008 PLC (± 2 μm / ± 80 μ-inches)	± 0.008 PLC (± 2 μm / ± 80 μ-inches)
Contact Load	Fixed - 113 grams	Adjustable minimum 4 grams	Adjustable minimum 4 grams	Adjustable minimum 4 grams	Adjustable minimum 4 grams
Temperature Control	Orton User Programmable, 20-segment, PID Controller with Melting Point Protection
Heat-up Rate	1 to 30°C/minute at 0.01°C increments	1 to 30°C/minute at 0.01°C increments	1 to 30°C/minute at 0.01°C increments	1 to 30°C/minute at 0.01°C increments	1 to 15°C/minute at 0.01°C increments
Data Acquisition	Orton On-board Computer (data stored in on-board computer at 1°C increments, downloaded to independent PC system)
Data Analysis	Orton Data Analysis Software 2
Computer Interface	RS232 Cable for user's PC 2
Standard Calibration	Factory Calibration using a 1" rod of High Purity Platinum Thermal Expansion Standard
Calibration Material	Pt available as an Option	1" copper standard include Pt available as an Option	Pt available as an Option	Pt available as an Option	Pt available as an Option
Reproducibility Sample	1" high alumina included	1" high alumina included	1" high alumina included	1" high alumina included	1" high alumina included
Controlled Atmosphere Option	Not Available	Yes	Yes	Yes	Yes
Bench-top Footprint (open) Length x Depth x Height	28" x 14" x 15" (710 x 360 x 380 mm)	49" x 14" x 24" (1,250 x 360 x 600 mm)	49" x 14" x 17" (1,250 x 360 x 430 mm)	49" x 14" x 17" (1,250 x 360 x 430 mm)	56" x 14" x 17" (1,420 x 360 x 430 mm)
Transformer Footprint	N/A	N/A	N/A	N/A	12" x 9" x 10" (305 x 230 x 250 mm)
Power Requirements (240 VAC, 50 Hz available)	120 VAC, 15 amp, 50/60 Hz	120 VAC, 15 amp, 50/60 Hz	120 VAC, 15 amp, 50/60 Hz	120 VAC, 15 amp, 50/60 Hz	240 VAC, 20 amp, 50/60 Hz

¹for a description and discussion of these specifications
²(Requires English Language Version of Windows 95/98/2000/XP)

Computer Analysis

Every Orton dilatometer is supplied with the software to add to the user's PC in order to acquire, save and analyze the data generated by the dilatometer. The Orton Dilatometer Software is written for Windows 95/98/2000/XP/Vista English language based personal computers. It can be used to monitor the dilatometer test in real time, or can be used to examine the test data after the run. The software imports the data through the RS232 interface (USB interface is available), and stores it on the hard drive for immediate or post-testing analysis. The software enables the user to:

View the dilatometer data in a variety of presentations:

• Percent linear change (PLC) vs. temperature
• Percent linear change (PLC) vs. time
• First derivative of the percent linear change (DCE) vs. temperature
• First derivative of the percent linear change (DCE) vs. time
• Percent linear change (PLC) and first derivative of the percent linear change (DCE) vs. temperature
• Percent linear change (PLC) and first derivative of the percent linear change (DCE) vs. time

Perform a variety of analyses:

• Calculate the coefficient of thermal expansion (CTE) between specified temperatures, or a series of specified temperatures
• Calculate the average coefficient of thermal expansion from room temperature to a specified temperature at a specified temperature increment
• Determine glass transition temperature (for ceramic glasses with TG’s between 400°C and 850°C)
• Determine softening temperature
• Locate alpha-beta quartz transition
• Export the data in a text file format for independent analysis or archiving purposes

Principle of Operation

The sketch above shows the concepts of a dilatometer. A sample specimen is placed between the end of the sample holder and the end of the movable probe rod, and the furnace is heated according to a pre-programmed thermal cycle. As the sample temperature changes (as recorded by the sample thermocouple), the sample expands (pushing against the probe rod) or shrinks (pulling away from the probe rod). The probe rod transmits the amount of sample movement to an electronic displacement sensor located outside of the heated chamber. The displacement sensor generates an electronic signal corresponding to the positive or negative change in sample length and continuously sends the signal to the computer. The computer converts the signal to the percent of length change (%DL) and saves it along with the elapsed time and the sample temperature. The basic TDA curve is generated by plotting the percent of length change (%DL) on the Y-axis against the sample temperature.

Horizontal Dilatometer

The photos above are a horizontal dilatometer with the furnace moved away to expose the sample holder, and a close-up view of the sample holder. The photo on the right shows how the sample is positioned between the end of the sample holder and the probe rod. After positioning the sample in the sample holder, the furnace is moved horizontally to surround the sample and sample holder.

The probe rod extends from the end of the sample, throught the sample holder tube, and connects to the displacement sensor assembly outside the furnace. The probe rod is spring loaded outside the furnace to keep it in constant contact with the sample, even when shrinking.

The main advantage of the horizontal system is the uniform temperature zone for the sample. Most dilatometer tests are performed with a horizontal unit.

Vertical Dilatometer

For larger samples, such as refractories and structural clay bodies, a vertical dilatometer is used. The sample is placed into the furnace and the vertical probe rod is lowered to contact the sample (as shown in the photo at the right). The furnace is heated according to the pre-programmed thermal cycle. As the sample temperature changes, the sample expands, pushing up on the probe rod, or shrinks, pulling away from the probe rod. The probe rod is vertically suspended and counterweighted so that gravity keeps it in constant contact with the sample. The probe rod transmits the amount of sample movement to the electronic displacement sensor located overhead and outside the furnace.

Orton also designs and manufactures other types of non-standard dilatometers, including vertical, multiple sample, metallurgical, quenching, laser, and special application systems.