Mettler thermoanalyzer

The preparation of Ba02 was carried out by decomposition of BaC03 in high vacuum 10-6 mm on the thermobalance (METTLER Thermoanalyzer) at 800 °C to BaO and subsequent oxidation with dry oxygen (Fig. 55). The complete oxidation could be achieved only after cycling in the temperature region 500 to 600 °C. 

The first combination of thermogravimetry (TG) and a mass spectrometer was by Zitomer (36) in 1968 who coupled a Du Pont thermobalance with a time-of-flight mass spectrometer. He applied the technique to the thermal decomposition of various polymers. Lastly, Wiedemann (37) described an elaborate TG-DTA-EGD-MS system in 1969. The system consisted of a Mettler thermoanalyzer couple to a Balzer quadrupole mass spectrometer that permitted the sample to be studied at low (10 6 Torr) or normal (I atm) pressures. 

Perhaps the most widely used TG-MS system, which includes DTG. DTA, and gas pressure measurements, is the Mettler thermoanalyzer. The system, which consists of a precision thermobalance, a high-vacuum system, a mass spectrometer, and a DTA measuring system, has been described in detail by numerous investigators (68-73). 

In almost every system, the Mettler Thermoanalyzer I was coupled to a quadrupole mass spectrometer, such as is illustrated in Figure 8.14 (37. 69i. The sample may be studied under vacuum 10"6 Tom or under higher pressures to 1 atm. The reaction chamber, R. is surrounded by the furnace and separated from the balance by a diffusion baffle. The evolved gases pass directly to the mass analyzer. F. which is connected to a recorder, J. through the mass spectrometer control panel. Total pressure is determined by an ionization gauge, S, which also permits the recording of the EGD curve (in this case, due to the pressure change in the system). The relation between measured total pressure and the ion current of the calibration gas permits calibration of the mass spectrometer in absolute partial pressure units or A/Torr. 

Figures 4.192 and 4.193 represent a series of curves obtained with a Mettler Thermoanalyzer similar to the one shown in Fig. 4.181. Each graph represents two TGA traces, TGI and TG2, of low and high sensitivity, and a DTA curve. The top of Fig. 4.192 is of a kaolinite from South Carolina. Between 700 and 1000 K, water is...

A typical thermogravimetric system is illustrated in Figs. 7.2 and 73, based on the classical, high-precision instrument, the Mettler Thermoanalyzer, first described in detail by Wiedemann in 1964. The left top sketch in Fig. 72 shows a view of a basic thermoanalyzer installation. The center table provides space for the high temperature furnace, the balance, and the basic vacuum equipment. The cabinet on the right houses the control electronics and the recorder. On the left is the work bench and gas cleaning setup. 

An analysis of praseodymium dioxide, also called praseodymium(IV) oxide, in a variety of atmospheres is shown in Fig. 7.8. The measurements were carried out with a Mettler Thermoanalyzer as described in Fig. 7,2. The furnace arrangement was similar to the one shown in the bottom right diagram of Fig. 7.3. The heating rate was 8 K/min, the gas flow was about 10 liter/h at atmospheric pressure, and the sample mass was about 3 g of black Pr02. The thermogravimetry curves of Fig. 7.8 are recalculated in terms of the chemical composition of the praseodymium oxides. 

TG-DTG-DTA-T-P, Mettler Instrument Corporation, Company Brochure 79) TA 2000 C, Thermoanalyzer for Simultaneous TG-DSC,... 

Glass temperatures have been determined by the DTA method with two different instruments (a Mettler differential thermoanalyzer and a Perkin-Elmer differential scanning calorimeter DSC 1) (9) in two different laboratories. They are listed in the two last columns of Table I. Small differences of 0°—7°C. were observed. This order of agreement was sufficient. 

Because of the suspected decomposition of anhydrite, CaSO4, in lithium-based tetraborate flux systems at elevated temperatures, it was decided to study their behavior by means of thennal analysis (TGA, DTA). Thermal scans were performed on the Mettler TA-2 thermoanalyzer equipped with a DTA-20 macroholder. Platinum crucibles were filled with 200 mg of specimen flux mixtures and balanced by equal portions of alumina as the reference material. All specimens were heated at a rate of 10 C/min in an oxidation atmosphere (stream of air). 

The Mettler TA1 thermoanalyzer, as developed by Wiedemann (3, 60), was perhaps the most elaborate and versatile of any thermobalance ever constructed. It is no longer available commercially, having been superseded by the Mettler TA 2000 and TA 3000 systems. However, because of its uniqueness, the Mettler TAl is described here. 

The Mettler TA 2000 C chermoanalyzer system permits simultaneous TG-DSC measurements from 25-1200cC at pressures from atmospheric to 10 5 mbar. With a special furnace, a corrosive gas atmosphere can also be used. A schematic diagram of the thermoanalyzer is shown in Figure 3.24. 

Bart et al. (62) have described the enclosure of a Mettler TA-1 thermoanalyzer in a sealed system in order to permit the examination of samples containing alpha and beta/gamma emissions. Samples containing plutonium and uranium may be studied by TG with no radiation hazard to the operator. All balance components could be reached through glove ports. 

The Mettler TA 2000C thermoanalyzer is a simultaneous 1 G-DSC instrument that has been previously described in Chapter 3. The data reduction... 

Yuen et al. (5) have described an automatic data acquisition system for the simultaneous operation of two Mettler Model TA-I Thermoanalyzers. A... 

Concurrent with the DSC and the TMA measurements, the water content of the polymer under study was determined thermogravimetri-cally (TG) with a Mettler TA-1 thermoanalyzer. The sample was contained in a quartz cylindrical crucible and was heated to decomposition at 10 C/min under a nitrogen flow of about 8 J2-/hr. 

As a control, a blank run with the empty crucible was also conducted. To assist the TG determination for water, simultaneous thermogravi-metric - mass spectral analyses (TG/MS) were also performed under a helium atmosphere on PS-2806, PS-2220 and PS-4652 using a tandem instrument consisting of a Mettler TA-1 thermoanalyzer and a Hewlett-Packard 5992 quadrupole mass spectrometer. ... 

Thermogravimetric- (TG) and differential scanning calorimetric- (DSC) studies were carried out using a Mettler TA 2000C thermoanalyzer. Measurements were performed under air with a heating rate of 10 K min. ... 

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