Simultaneous TGA-DTA Analyzer

What is the Simultaneous TGA-DTA Analyzer?

A simultaneous TGA-DTA analyzer pairs a thermobalance with a differential thermal sensor that is robust at high temperature, recording mass loss and endothermic or exothermic peaks up to 1600 degrees Celsius for ceramics, minerals, cements and metals.

Overview

The DTA sensor consists of thermocouples or a plate that measures the temperature difference between sample and reference positions, which remains reliable where heat-flow sensors would suffer from radiation losses and material limits. As a result the configuration covers ambient to 1500 or 1600 degrees Celsius in air, argon or nitrogen, with the balance protected by a counter-flow of purge gas. Mass loss onsets and residue are reported with the thermal peak temperatures, making it possible to distinguish, for example, dehydration from dehydroxylation and decarbonation in clays, or to identify gypsum dehydration steps and clinker formation events in cement. Samples of 20 to 200 milligrams are typical because inorganic reaction heats are small. The thermal signal is mainly qualitative, so enthalpies are not normally reported, but the correspondence between mass steps and peaks is the principal output.

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?

• DTA sensor operating to 1500–1600 °C in air or inert gas
• Simultaneous mass loss and thermal peak correlation
• Balance protection by counter-flow purge gas
• Alumina, platinum or graphite crucible options
• Temperature calibration with melting point standards
• Software reporting mass step onsets with peak temperatures

What are the technical specifications?

A typical simultaneous tga-dta analyzer configuration offers temperature range of Ambient–1600 °C, balance resolution of 0.1 µg, DTA signal resolution of 0.5 °C, temperature accuracy of ±3 °C, heating rate of 0.1–30 °C/min and sample mass of 20–200 mg typical. 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 Simultaneous TGA-DTA Analyzer is used in clay and mineral dehydration studies, cement and gypsum analysis, ceramic and refractory reactions, carbonate and sulfate decomposition and oxide reduction and oxidation. 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 Simultaneous TGA-DTA Analyzer?

Select the TGA-DTA configuration for inorganic materials above 700 degrees Celsius where peak temperatures plus mass loss are the required output. For quantitative enthalpies of organics, a TGA-DSC sensor is better. In an RFQ, specify maximum temperature, thermocouple type, crucible material and gas control.

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.