Determinations des temperatures et des pressions par spectrometric Raman au cours de la CVT du nickel

Article abstract of DOI:10.1016/0584-8539(88)80066-7

Nickel CVT, based on the following chemical equilibrium: Ni_(s) + 4CO_(g) <*> Ni(CO)4_(g), has been studied by Raman spectroscopy.The temperature of the gaseous mixture can be calculated from the experimental intensities of CO rotational Raman-Stokes lines.The simulation of CO spectrum has been made from the theoretical intensities of lines convoluted with functions taking account of the incident band shape (Gaussian function) and slit geometry (apparatus function).Simulated and experimental spectra are in a good agreement and the calculated temperature is found with a precision of one Celsius degree compared with the temperature at 1/10 deg C precisely.From the Ni(CO)4 vibration V_S(Al) at 370.6 cm^-1 available both in Stokes and anti-Stokes fields, we have another method of temperature calculation (SAS method).At a known temperature, the same vibration can be used to compute the partial pressure of Ni(CO)4.Results obtained are compared with those directly measured with a tensimeter.The temperature and the pressure respectively determined from the CO rotation lines and the Ni-C symmetric streching vibration at 370.6 cm^- permit us to follow the nickel CVT in a transparent furnace (SnO2 technology).