THERMAL TRENDS 2

Table of content

L75/SDC simultaneous-Dilatometer/Calorimeter

L75/SDD simultaneous Dilatometer/DTA

L81/RITA high speed Thermo Balance

Quattro Dilatometer

L75/1250/B/S Macro Dilatometer

L76/1000B Low Cost Dilatometer

New air cooled furnace program

Impressum

Softening Point Software for Dilatometer

Dilatometer sample holder for powders

L75 / SDCS imultaneous

D ilatometer Calorimeter

Sample holders

Sample#2

Sample#1

Push rods

With the newly developed Linseis SDC Software it is possible to get results on a Dilatometer not only for expansion coefficients (CTE). Using the same hardware you can measure the caloric properties of the sample, heat capacities, enthalpies and phase transitions are available. The SDC Software utilizes the dual sample Dilatometer’s capability. Two samples of the same material, same length, and different diameters are used.

Because both samples have different volume and mass, (different heat capacity) the temperature that can be measured at both samples during a heating or cooling phase are different. The larger sample is temperature wise “behind” the smaller sample. As the temperatures measured at both samples are thus different at specific times, the corresponding delta L / expansion signal is also different. The principle of the SDC Software is to maintain a constant length difference between sample one and sample two throughout the test. This is accomplished by varying the applied heating and/or cooling rate.

The heating and/or cooling profile is now proportional to the heat capacity of the sample material. The result are Endothermic and exothermic peaks displaying phase transitions of the sample based on the resulting heating and/or cooling rates. Absolute values can be obtained by running calibration two samples of known heat capacity and known mass.

SimultaneousL75 / SDD

D

ilatometer DTA

Standard dilatometer measurement with additional DTA evaluation.

By means of this software any normal installed Linseis Dilatometer is now able to achieve additional DTA information / enthalpy values out of Dilatometer runs. Typical Dilatometer measurements usually determine the expansion delta L and expansion coefficient CTE of a sample. Very often the samples display an endothermal or exothermal reaction. These reactions cause a very small effect to the normally constant heating or cooling rate. For example if the sample requires energy during a phase transition, it will draw this energy from of the Dilatometer measuring system. In turn the furnace controller will compensate for this heat loss in order to obtain a constant heat up rate.

These small deviations in the constant heating rate and the real temperature signal which is obtained from a heat loss or gain result in the DTA signal. The actual measured values are compared to a calculated heating or cooling curve. Using this procedure it is possible to get caloric enthalpy measurements from a Dilatometer.

On next page we show an example of this software where the Alpha / Beta transition of quartz is shown. The sample had a mass of 450mg and a volume of 3x4x5mm. The transition is endothermic during the heating phase and exothermic during the cooling phase. The measured value of the onset temperature is 573°C and it is identical to the literature value. To get these results, a normal Dilatometer measurement file is loaded. Next the Dilatometer file is changed into a DTA curve format. DTA evaluation can now be displayed using normal procedure for evaluating onset and offset temperatures.

Simultaneous D

ilatometer L75 / SDD

DTA

High Speed Thermal Balance L81/RITA

Picture: L81/RITA high speed Thermal balance

Picture: Inductive furnance

RITA – Rapid Inductive Thermal Analysis

The high speed thermal balance L81/RITA was developed to measure the weight change signal during rapid temperature changes (up to 100K/s). The basic balance that is used is our well proven L81 series balance. The normal slower resistance type furnace is replaced with a faster induction furnace which results in very fast heating and cooling rates. The induction furnace normally works only with metallic materials; however other samples can be measured using a metallic crucible which will transfer heat to the sample.

High Speed Thermal Balance L81/RITARITA – Rapid Inductive Thermal Analysis

Picture: Sample up to 1000°C

Space Shuttle &

The initial application for the system was a space application.

Researchers are investigating materials and looking for the exact mass change during the atmosphere reentry phase of a space vehicle.

Within seconds, a space tile will display a large mass loss.

Using the L81/RITA system this rapid mass change can be measured.

The L81/RITA also employs our automatic gas control system which controls the sample atmosphere for measurements in inert and vacuum environments.

As there is no big mass of a normally used resistance furnace, measurements can be done within seconds. The system stays cool, even the protection tube is cool.

DilatometerQuattro

Picture: Quattro Dilatometer

Picture: 4 times measurement head

The Linseis has developed a new dilatometer which is capable of measuring 4 samples at the simultaneously. The major advantages of the “Cuatro Dilatometer” are:

- Increased productivity for QC application

- Reduced overall costs by only

using 1 instrument and less lab space required.

Better accuracy by testing 3 samples and a standard simultaneously.

Less variability when using a single furnace for 4 samples.

The system will acquire and evaluate 4 independent samples.

Quattro Dilatometer

Picture: 4 times sample holders

Picture: 4 times measuring head

MEASURING SYSTEM The measuring system is a contact pushrod design. Force is applied through the pushrod to the sample using by expanding a spring. The automatic load control is an option which can be installed on each sample pushrod. The sample force is set using a potentiometer and digital display. A constant force will be applied to the sample throughout the expansion or shrinkage of the sample.

By Deformation of fragile samples is reduced by applying a constant force throughout the test. Varying the force is as easy a turning a dial.

The constant load can be adjusted for each sample individually. The initial sample length is independent for each sample as well.

The 4 sample dilatometer is available as a Horizontal or Vertical measuring system. Depending on your application each system has it’s advantages. The initial zero point for each sample is adjusted independently through the software. There are no mechanical adjustments needed.

Quattro Dilatometer

Picture: Evaluation of quattro dilatometer measurement

Picture: 4 times amplifier

Macro Dilatometer L75/1250B/S

Picture: Macro Dilatometer L75/1250/B/S

Picture: Integrated protection tube

Picture: long sample

The recently developed Macro Dilatometer has the ability to measure larger samples up to 120mm in length and 16mm in diameter.

It operates from room temperature to 1000°C and is capable of measuring samples in vacuum or inert atmospheres.

The protection tube is mounted within the furnace and is retracted along with the furnace. This allows for easier handling and changing of the sample.

Macro Dilatometer L75/1250B/S

Picture: Special furnance

Picture: protection tube, sample holder

Picture: Gas control

The Macro furnace has longer hot zone and a minimal temperature gradient over the long sample.

Optional on the Macro dilatometer include a gas control system.

Various gases can be introduced to the sample either manually or automatically using the software.

A Common application for this dilatometer is the measurement of carbon which has a large particle size. Due to the large particle size longer samples with greater diameters must be used to acquire a accurate value for CTE and length change. Optional closed cooling systems are available which eliminates the need for tab water.

Low - Cost Dilatometer L76/1000B

Picture: L76/1000B Dilatometer Linseis now offers a low cost single sample Dilatometer. The L76/1000B can be used for basic expansion or shrinkage measurements from RT up to 1000°C. We are able to lower the cost on this unit by using universal components and eliminating the vacuum and atmosphere control option. The unit will measure expansion and /or shrinkage from room temperature to 1000oC in standard air. The evaluation of data includes CTE, % expansion or shrinkage, absolute expansion or shrinkage, and more. The sensor employed is an LVDT (linear variable differential transformer) which is very precise. This LVDT has theoretically an indefinite resolution. For this application the resolution is 14nm (nanometer). This is the same dimension as the wavelength of light. This type of standard dilatometer is often used for quality control measurements in the glass or ceramic industry that normally are made inert gas flows or vacuum. There are several advantages of the new low cost design. We have eliminated the need for water cooling on the furnace; also there is no need for a water circulating bath to maintain a constant temperature on the measuring head. The sensor module or measuring head is equipped with a sensor electronically regulates and maintains measuring head temperature slightly above room temperature. Another very useful feature is the automatic zero setting of the LVDT sensor. This option eliminates and micrometer screws to adjust the LVDT zero position. The LVDT is positioned using an internal motor controlled via the software. Different sample lengths are automatically adjust and can vary from nearly 0 to 50 millimeters in length.

Air-cooled furnance

Picture: Air-cooled furnance

The latest development in furnaces is our air cooled furnace. These furnaces offer several advantages; there is no need for cooling water. Also they have a quicker cooling times affording a shorter cycle time and giving you more runs in a work shift. The cool down time is reduced to about half the time necessary to cool a water cooled furnace. An internal protection tube is another feature of the new air cooled furnaces. The protection remains inside the furnace as the furnace is retracted from the sample holder. This added feature makes changing samples easier and quicker.

Air-cooled furnance

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ilatometer sample holder for powders

D

Push rod

Sample holder

Sample holder

Sample (ex: powder)

In response to customer requests to test powder samples in the dilatometer, Linseis has developed a new powder sample holder. Using the new powder sample holder it is now possible to test powders and examine binder burnout, CTE, and sintering using a standard sample holder along with the optional powder sampler holder. The powder sample holders are available made from Al2O3, quartz, and graphite. There are two versions available, one with fixed end and movable push rod. The other version has two movable push rods inserted in the holding sleeve. The powder container can be used in horizontal or vertical dilatometers.

Sample holders samplePush rods

S

oftening Point Software für Dilatometers

All dilatometer delivered since 01. 11. 2002 has a new feature included in the WIN-DIL software. Softening point feature to determine the softening point of a sample is a standard feature now. It is now part of the standard functions of the WIN/DIL software program at no extra cost.

The feature not only determines the softening point of the sample, but it also protects the measuring system from a sample melting sample. With the softening point feature is activated, if a sample softens or shrinks more than the preset amount the controller will switch to a cooling cycle. The softening of the sample is detected when the expansion of the sample reaches a maximum and starts shrinking again. The amount of shrinking after a maximum can be freely programmed. It is also possible to program different shrinkage factors for each heating stage. The normal temperature control program enables 16 different segments with different heating rates, cooling rates, and dwell times. The same software feature can also control for expansion events. This is another way of controlling the dilatometer if an event occurs.

LINSEIS GmbHVielitzerstr. 43

95100 SelbGermany

Tel.: (+49) 9287–880 - 0Fax: (+49) 9287–70488E-mail:info@linseis.de

LINSEIS Inc.�0 Washington RoadP.O.Box 666Princeton-Jct. NJ 08550Tel.: (609) 799–6282Fax: (609) 799–7739E-mail: info@linseis.com

www.linseis.com

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