Evaluation of Accuracy and Reproducibility of a High-temperature Differential Scanning Calorimeter by Specific Heat and Enthalpy of Fusion Measurements
Author: Susan Jacob
Publisher:
Published: 2006
Total Pages: 0
ISBN-13:
DOWNLOAD EBOOK"This thesis focuses on developing a set of optimum experimental parameters for high-temperature differential scanning calorimetry. A high-temperature differential scanning calorimeter (HTDSC) was used to check the accuracy and uncertainty of HTDSC measurements upon varying experimental parameters. A set of experimental variables was selected and specific heat or enthalpy of fusion measurements were carried out as case studies. The specific heat of platinum was measured from room temperature to 1400°C by varying heating rate, sample mass, cover gas flow rate, and standard material. Reproducible data were obtained for all the runs except for those made using a thinner platinum sample. Accuracy close to 1% was achieved. Accurate and reproducible heat capacity measurements were given by: a. higher heating rate b. standard material of the same size, mass, and geometry that of the sample, and c. larger sample mass. For heat of fusion of silver measurements, the type of crucible was also varied to determine its impact on instrument accuracy and reproducibility. Good reproducibility was achieved in the majority of the runs. Accuracy was not satisfactory in most of the runs, though three experimental conditions gave results within 1.7%, 3.3% and 3.5% of the literature value, within the acceptable limits. A larger mass and higher heating rate tended to improve accuracy. Considering the choice of crucibles, alumina-lined platinum crucibles gave better results. Choosing the right experimental conditions and with very careful use, it is possible to obtain accurate and reproducible results using a high-temperature differential scanning calorimeter"--Abstract, leaf iii
