Metal calibration standards indium

The melting transition of ultra-pure metals is usually used for calibration of DSC instruments. Metals such as indium, lead, and zinc are useful and cover the usual temperature range of interest. Calibration of DSC instruments can be extended to temperatures other than the melting points of the standard materials applied through the recording of specific heat capacity of a standard material (e.g., sapphire) over the temperature range of interest. Several procedures for the performance of a DSC experiment and the calibration of the equipment are available [84-86]. A typical sensitivity of DSC apparatus is approximately 1 to 20 W/kg [15, 87]. 

Calibration of the instrument for its response to length may be carried out with a standard length piece of metal or ceramic. The temperature can be calibrated in the same way as for DSC. Metal standards such as indium, tin, or lead are mostly used. Recent publica-tions ° deal with calibration and errors of TMA. 

The DSC peak area must be calibrated for enthalpy measurements. The same types of high purity metals and salts from NIST discussed for calibration of DTA equipment are also used to calibrate DSC instmments. As an example, NIST SRM 2232 is a 1 g piece of high purity indium metal for calibration of DSC and DTA equipment. The indium SRM is certified to have a temperature of fusion equal to 156.5985°C + 0.00034°C and a certihed enthalpy of fusion equal to 28.51 + 0.19 J/g. NIST offers a range of similar standards. These materials and their certified values can be found on the NIST website at www.nist.gov. Government standards organizations in other countries offer similar reference materials. 

Figure 6. Storage permittivity during a temperature scan in a dielectric relaxation spectrometer using indium as the standard, according to the inset scheme, recorded at 1 C min" and measured at two frequencies (squares 500 Hz, circles 1000 Hz). Inset set-up for the calibration of a DRS equipment using metallic standards A-electrodes of the equipment, B- metallic plaques, C- polyimide films, D- metallic standard. The results were adapted from [30].

Temperature, force, probe and cell constant calibrations were carried out as prescribed [7], using NIST standards of indium, lead, tin and zinc metals along... 

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