Thermal analysis — review and prospect

Abstract

The history of thermal analysis is briefly reviewed, focusing on fundamental aspects, such as quantitative measurement by DTA, kinetics, purity determination, sample-controlled thermal analysis and temperature modulation. Several general trends, commonly seen in the history of thermal analysis, are also pointed out. Among these trends are new techniques, new application fields, diffusion of the techniques from research to quality assurance, computerization and robotics, infrastructure, such as standardization, etc. In this overview, new techniques and methods of thermal analysis are examined and directions of future progress are anticipated for its sound development.

Introduction

Thermal analysis has now had more than eleven decades of history. During this long history, various techniques were invented and thermal analysis has been used in many fields. Nowadays, the application of thermal analysis spreads among minerals, inorganic substances, metals, ceramics, electronics materials, polymers, organic substances, pharmaceuticals, foodstuff and biological organisms. While application in each field began in research, it has been diffusing through development into control of processes and qualities. Today, thermal analysis is an essential tool for materials research and development, while quality assurance is now one of the ‘hot topics’ in thermal analysis.

In research into high-temperature superconducting oxide materials, we saw one of the most vivid examples of its versatility. Since the end of 1986, research was stimulated by the discovery of a new oxide material, and a boom occurred in research into these materials. In the course of this boom, various thermal-analysis techniques were used for a variety of purposes [1] as listed in Table 1, and from this the readership can realize versatility of thermal analysis. This is one typical example and the situation is quite similar in other fields of research and development.

Considering the long history of these steady developments, it is often thought that thermal analysis is already so mature that there is little room for further progress, as in the case of infrared spectroscopy. In this technique, progress has not been remarkable for a few decades, though it has been used in various fields as an analytical tool. However, this is not the case with thermal analysis. Just as new frontiers have been explored in magnetic spectroscopy, such as magnetic resonance imaging, new trends and further progress have also been made in thermal analysis and these will be discussed here.

On the other hand, it is also observed that some of the progress is not grounded on sound physical bases. Therefore, critical reviews of these progresses are essential for furtherance and development of thermal analysis. The author has tried to make such reviews and to summarize them in this brief article. Naturally, it is made from the author’s own viewpoint, mostly based on his experience, and, hence, it is neither comprehensive nor free from bias.