High-Temperature Simultaneous Thermal Analyzer

What is the High-Temperature Simultaneous Thermal Analyzer?

A high-temperature simultaneous thermal analyzer reaches 1500 to 1600 degrees Celsius with an alumina or graphite furnace, tracking mass loss and heat effects in refractories, ceramics, slags, cements, catalysts and metal oxides in one run.

Overview

The furnace uses silicon carbide, molybdenum disilicide or graphite elements and the sample carrier is made from alumina, sapphire or graphite, so measurements can be made in air, argon, nitrogen or vacuum. Balance and sensor drift are the limiting factors at these temperatures, so a counter-flow purge and long isothermal stabilisation are used before the ramp begins. Typical specifications include a temperature range from ambient to 1600 degrees Celsius, heating rates of 0.1 to 30 degrees Celsius per minute, a balance resolution of 1 microgram and a DTA or heat-flow signal accurate to a few degrees Celsius. Applications include carbonate and sulfate decomposition, reduction of iron ore and metal oxides, coke and sulfur content of catalysts, ceramic binder burnout and gas evolution from refractory binders. The combination is particularly useful when a mass loss step and a thermal event occur in the same temperature window and must be separated.

How does it work?

The instrument combines a thermobalance with a heat-flow or differential thermal sensor on a single sample holder inside one furnace, so mass and thermal signals share exactly the same temperature, heating rate and atmosphere. Because there is no second sample, results cannot be offset by sample-to-sample variation in mass, particle size or packing, which is the main advantage over running a TGA and a DSC separately. The heat-flow signal can be calibrated with indium to give melting enthalpies and heat capacity, while the balance gives mass loss steps, derivative peaks and residue. Typical temperature ranges extend from ambient to 1500 or 1600 degrees Celsius, with balance resolution of 0.1 microgram and heating rates of 0.1 to 50 degrees Celsius per minute. Purge gas is switched between inert and oxidising conditions, and a reference crucible is placed on the sensor alongside the sample crucible.

What are the key features?

• Furnace to 1600 °C with silicon carbide, MoSi₂ or graphite elements
• Counter-flow purge protecting the balance from condensables
• Alumina, sapphire or graphite sample carriers
• Air, argon, nitrogen or vacuum atmosphere options
• Long isothermal stabilisation before the temperature ramp
• Combined evaluation of mass steps and thermal events

What are the technical specifications?

A typical high-temperature simultaneous thermal analyzer configuration offers temperature range of Ambient–1600 °C, balance resolution of 1 µg, balance capacity of 5 g, heating rate of 0.1–30 °C/min, temperature accuracy of ±3 °C and thermal signal accuracy of ±5 °C. Values are indicative of the product class; the exact figures for each configuration are confirmed on the quotation and the calibration documents supplied with the instrument.

Which applications is it used for?

The High-Temperature Simultaneous Thermal Analyzer is used in refractory binder burnout, iron ore and oxide reduction, catalyst coke and sulfur determination, cement raw meal and clinker reactions and slag and mineral decomposition. Across the wider Simultaneous Thermal Analyzers class, laboratories also deploy it for polymer composition and additive analysis, pharmaceutical hydrate and polymorph studies and ceramic and mineral reaction analysis.

Which standards and certifications apply?

Relevant standards and methods include ASTM E1131, ASTM E967, ASTM E794, ISO 11358-1, ISO 11357-1 and USP <891>. Certification candidates for this model are CE, IEC 61010-1 safety and ISO 9001 manufacturing; each is to be confirmed for the specific configuration before shipment, and certificates are supplied only where they have been issued.

Prepare sample and reference crucibles in the same way, with similar mass and packing, because the heat-flow signal depends on the symmetry of the two positions. Keep the balance purge flow stable and high enough to protect the weighing mechanism from condensable products, and verify with a blank run whenever the gas or flow changes. Calibrate temperature with Curie-point or melting-point standards and heat flow with indium before a critical campaign, and record crucible type, gas, flow, heating rate and sample mass with each curve. Simultaneous instruments show artefacts when the two crucibles differ: a sloping or drifting heat-flow baseline usually means asymmetry, damaged crucibles or contaminated sensors. Coupled techniques add transfer line maintenance, and the interface temperature must always be above the dew point of the evolved gases.

How do I select the right High-Temperature Simultaneous Thermal Analyzer?

Specify the high-temperature configuration when inorganic reactions above 1000 degrees Celsius must be studied with both mass and thermal information. For organic materials, a lower-temperature instrument with heat-flow calibration gives better sensitivity. In an RFQ, state maximum temperature, atmosphere, sample carrier material and expected hold times.

How does it compare with other Simultaneous Thermal Analyzers variants?

Choose between the TGA-DSC and TGA-DTA sensor types first. A heat-flow sensor calibrated with indium gives quantitative enthalpies and heat capacity and suits polymers, pharmaceuticals and organics; a DTA sensor is more robust at high temperature and suits ceramics, minerals and metals where peak temperatures are enough. Then set the temperature range, since inorganic materials may need 1500 or 1600 degrees Celsius while organics require sub-ambient cooling. Decide whether evolved gases must be identified, which determines whether an FTIR or mass spectrometer coupling is needed. Check balance resolution, whether the crucible arrangement allows gas to flow over the sample, the gas switching capability, the software for combined signal evaluation and the calibration standards provided. For quality control, an autosampler converts the instrument into an unattended routine analyzer.