Researchers at the Instituto de Ciencia de Materiales de Sevilla are analysing the kinetics of solid state reactions by heating (or cooling) a sample and plotting its weight as a function of time or temperature. Analyses are used to investigate the underlying mechanism by which a material decomposes or recombines. Professor José M Criado, who heads the team, has developed a set of apparatus for this work, at the heart of which is a CI Mk2 microbalance head from CI Precision.
The sample under analysis is suspended from the microbalance head, enabling an accurate measure of its mass to be obtained with a resolution of 0.1ug. The sample is heated by a furnace, also from CI Precision, with the sample temperature monitored by a thermocouple. A CI DISBAL control unit is connected to the microbalance head and provides an analogue output signal that indicates the sample’s weight. Importantly, the researchers have used this output as a control input to the furnace temperature controller so that the heat input to the sample can be controlled in such a way that the sample’s rate of decomposition can be held at a constant value chosen by the user.
Using this Sample Controlled Thermal Analysis (SCTA) apparatus enables very low reaction rates to be controlled with significantly greater precision than is possible using alternative
The Seville team’s thermogravimetric analysis apparatus differs from that of other researchers in that the sample is contained in a vessel that can be either evacuated or pressurised. So far the maximum pressure used is 6 or 7 bar, but the vessel is currently being modified so that the pressure can be increased to 9 or even 10 bar.
One of the reasons why Professor Criado is using microbalances from CI Electronics is that the heads can be readily integrated within customised apparatus. Other reasons for using instruments from CI Precision include competitive pricing, high quality, reliability and exceptional customer service.
Professor Criado comments:
“We have a CI microbalance that is 35 years old and still working perfectly. In the past we had a problem with it and, despite it being so old, CI still went out of their way to help us get it working again. I don’t believe any other supplier of microbalances would do the same. And if we ever contact CI with a technical question, someone responds within a day. The level of technical service we receive is always very good.”
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