Investigation of Mechanisms for Oxidation Protection and Failure of Intermetallic Coatings for Refractory Metals. Part I. Molybdenum Disilicide


Book Description

An investigation of the oxidation behaviour and related characteristics of bulk silicides and silicide coatings of molybdenum and tungsten was conducted. The study included (a) the growth kinetics of disilicide coatings, (b) marker experiments to identify diffusing species during disilicide coating formation, (c) a thermochemical analysis of halide enhanced silicon vapor transport during coating processing, (d) the growth rates of intermediate silicides in the MoSi2/Mo and WSi2/W systems using an electron microprobe technique, (e) the microstructure of protective oxide films grown on MoSi2 and the nonprotective oxidation products formed at low temperatures, (f) an analysis of the oxidation process and the resultant chemistry of the oxidation products based on thermochemical and diffusion rate data, (g) an experimental and analytical treatment of oxidation of molybdenum silicides at high temperatures, to 1600C, and reduced oxygen pressures, and (h) a correlation of experimental coating failure times, in normal oxygen atmospheres, with the required time to transform primary disilicide coatings to lower nonprotective silicide phases. (Author).










Refractory Metal Alloys Metallurgy and Technology


Book Description

This publication documents Proceedings of the Symposium on Metal lurgy and Technology of Refractory Metal Alloys, held in Washington, D.C. at the Washington Hilton Hotel on April 25-26, 1968, under sponsorship of the Refractory Metals Committee, Institute of Metals Division, of the Metallurgical Society of AIME, and the National Aeronautics and Space Administration. The Symposium presented critical reviews of selected topics in refractory metal alloys, thereby contributing to an in-depth understanding of the state-of-the-art, and establishing a base line for further research, development, and application. This Symposium is fifth in a series of conferences on refractory metals, sponsored by the Metallurgical Society of AlME. Publications issuing from the conferences are valuable technical and historical source books, tracing the evolution of refractory metals from early laboratory alloying studies to their present status as useful engineering materials. Refractory metals are arbitrarily defined by melting point. A 0 melting temperature of over 3500 F was selected as the minimum for this Symposium, thus excluding chromium and vanadium, which logically could be treated with other refractory metals in Groups VA and VIA of the periodic table. The Refractory Metals Committee is planning reviews of chromium and vanadium in subsequent conferences.







Modern Materials


Book Description

Modern Materials: Advances in Development and Applications, Volume 5 provides comprehensive insight into the properties, applications, progress, and potentialities of various materials. This book is composed of four chapters, and begins with the presentation of the properties and application areas of coated refractory metals. The second chapter describes the special properties and utilization areas of hydrogen-precipitated powders and roll-compacted strip made from these metals and some of their related alloys. This chapter emphasizes the production processes of these materials. The third chapter deals first with a few general aspects of luminescence and phosphor synthesis, followed by significant discussions on the main fields of application of phosphors. The fourth chapter surveys concrete as an important construction material and its wide-array of application. This book is of great value to materials scientists and technologists.







Proceedings


Book Description