SETARAM Thermobalances

The MTB microbalance is cylindrical in shape and is mounted on a metal base that serves as a pumping block. It has a symmetrical beam type suspended on a taunt-band. Depending on the model, maximum mass capacity is 10, 50, or 100 g, with mass sensitivity of 0.4-10 fig. The balance may be used at pressures from 1 atm to 10 6 Torr. 

The conversion of Cahn electro balances to ihermobalances has been described by a number of investigators. For the Model RG balance, mention should be made of the instruments described by Gulbransen et al. (41), Feldman and Ramachandran (42), Pedersen (43), Etter and Smith (47), and numerous others 152) the Model RM is described by Scott and Harrison (44) and the Model RTL is described by Bradley and Wendlandt (45) and others (46). 

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Elemental composition of the calcined AIPO4 was determined by SEM-EDX (JEOL-JSM 6300, 20 kV). TG-DTA measurements were performed in flowing Ar (293-1173 K, 10 K min ) using a Setaram thermobalance Setsys-12. XRD patterns (CuK radiation) were developed in a Siemens D-5000 diffractometer. FT-Raman spectra were taken from compacted samples at 3600-200 cm (resolution 0.2 cm ), using a Perkin-Elmer System 2000 spectrometer. XPS were recorded on a Leybold-Heraeus LHS-10 spectrometer (at 10 Torr) using Al Ka radiation and a pass energy constant of 50 eV. A1, P and MAS-NMR spectra were recorded on a Bruker ACP-400 spectrometer. DRIFT spectra (4000-400 cm resolution 8 cm 256 scans) were recorded on a Bomem MB-100 FT-IR instrument equipped with an environmental chamber placed in a DRIFT attachment. DRIFT spectra were recorded for calcined materials (200 mesh size and diluted to 15 wt% KBr) previously vacuum-dried at 400 K for 24... 

X-ray powder diffraction patterns were obtained on oriented film specimens [7] (2 to 45° 2 , Philips PW 1120, monochromatized CuKa radiation, continuous peak registration). BET surface area and the pore volume distribution were determined from Nj adsorption-desorption isotherms at 77 K (degassing at 393 K, lO" mbar, 5h Sorptomatic 1900, Carlo Erba Instruments). The IR-spectra were recorded on KBr wafers [4] with a Specord 80M spectrometer. The XPS (X-ray photoelectron spectroscopy) spectra were obtained with VG ESCALAB 200 MKII spectrometer equipped with a twin anode AIKa source (1486 eV). The thermogravimetric (TGA) analyses were carried out with a Setaram TG 85 thermobalance at a heating rate of 6 K min in a helium flow of 30 ml min . The chromium content of the samples was determined by EPMA (JEOL 840 scanning electron microscope) with energy dispersive spectrometer (EDS, Tracer Northern) and by AAS (atomic absorption spectroscopy, Perkin Elmer 3030) analyses. 

X-Ray Diffraction (XRD) patterns were recorded on a Philips HTK-KC diffractometer with a CuKa X-ray source, linked to Philips 386 computer. Thermo-Gravimetry (TG), was recorded on a Setaram TG-DTA 92 thermobalance. Diffuse Reflectance Spectra (DRS) were recorded on a Cary-5 spectrofotometer with a BaS04 integration-sphere in the UV-VIS-NIR region. Mossbauer spectra are recorded on a vertical constant acceleration drive in transmission geometry with a 28mCi Co(Rh) source. Isomer shift data are expressed relative to metallic Fe at 293 K which has an isomer shift of8 = -0.0888 mm/s relative to natural a-Fe. 

TG-DTA patterns were recorded on a Setaram TG-DTA92 thermobalance. 

A TG-DSC instrument capable of sub-ambient temperature operation has been available for a number of years, and is especially valuable in the study of systems containing moisture, or other volatiles. In this case, a DSC heat flux plate was adapted to allow it to be suspended from the thermobalance beam, instead of the pair of thermocouples shown in Figure 1. A completely different approach to TG-DSC is taken by SETARAM, in their TG-DSC 111 instrument. The sample and reference... 

The adsorption isotherms of propane and n-pentane (purity > 99%, from Fluka) were obtained at constant pressure of 27kPa and at 373 and 523K in a Setaram MTB 10 thermobalance. The CaA adsorbents (Ao, A33, A44, and A57) were supplied by IFP and the 75% exchanged adsorbent (A75) was from Rhone-Poulenc. All these samples contain 80% wt.-% of zeolite and 20wt.-% of clay binder. 

Further research involved thermogravimetric analysis (TGA) of samples on the basis of F6203 and CaC03 (CF-25-75). Tape-cast and die-cut samples were sintered at 1000 °C and exposed to an atmosphere with a H20 H2 ratio of 4 1 at 800" for 12 h (discharged state). Then, samples were reduced isothermally at 800 °C in Ar+2%H2 using a thermobalance (Setaram S.A., France). 

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