Refractory Metals Reactive Metals
Production Applications
Ta Nb Mo Re W Zr Hf Ti V and Cr
Propert ies Economics
Twenty-four pages of details where these metals of growing CPI importance stand today
INCE THE BEGINNING of the historical epoch known as the atomic age and, more recently, also called the space age, laymen and scientists alike have become increasingly aware of the importance of solid-state physics and materials engineering in technological developments. Not all of these individuals are aware of the important role played by the chemical industry in the development of the materials field, particularly regarding those processes required to extract and purify materials. Further, the chemical industry itself has been able to take advantage of the special properties of some of the newer materials. For a number of years, I/EC has presented annually a review of new developments relating to the less common metals and their use as materials of construction. In the past three years, published technical literature dealing with the less common metals has appeared at a rapidly increasing rate. For example, the number of references which appeared in 1959 represented a fourfold increase over those available in 1956. Recognizing the growing importance of these elements, the Division of Industrial and Engineering Chemistry sponsored a symposium at the 138th National Meeting of the American Chemical Society. This symposium covered the metallic elements chromium, hafnium, molybdenum, niobium, rhenium, tantalum, titanium, tungsten, vanadium and zirconium. All of these elements are difficult to obtain in a state of high purity because of their affinity for atmospheric gases and carbon at relatively moderate temperatures. However, many of them have excellent mechanical properties at elevated temperatures. Hence, efforts have been made first to purify these metals and, second, to render them resistant to high temperature oxidation or corrosion by the use of protective coatings or of alloying. As reliable information has been developed, a clearer picture has formed of the advantages and disadvantages of each metal for specific applications. Enough is known about the technology and economics of the less common retsllic elements to make some predictions of their future utility.
E. M. SHERWOOD Battelle Memorial Institute, Columbus, Ohio VOL. 53, NO. 2
e
FEBRUARY 1961
89
