Radiocristallographie

Abstract

DURING the last twenty years X-ray crystallography has found many industrial applications in France as elsewhere. The present volume is written for the industrial man of science who requires a broad knowledge of the applications of the subject. The first chapter gives a short account of the properties of X-rays, the second chapter describes very briefly the types of X-ray tubes and high-tension equipment at present in use. The third chapter gives a summary of the theory of crystallography in so far as it is necessary for the determination of cell dimensions ; but it is the author's expressed intention not to include a discussion of space-groups or of the methods of finding actual atomic arrangements within the unit cell. Chapter 4 gives an account of the principles of X-ray powder photography, and Chapter 5 discusses the taking and interpretation of rot at ing-crystal and of Laue photographs. The concepts of the reciprocal lattice and of the reflecting sphere are used ; but the discussion of them is rather too brief to enable a serious student to understand the problems fully. The omission of moving-film photographs is surprising seeing how many applications they now have. One of the author's main contributions to recent developments in X-ray crystallography, namely, the use of the focusing monochromator, is described in Chapter 6. Though introduced originally by Johannsen in Sweden, the focusing monochromator has in recent years been more developed and applied in France than elsewhere. This book contains a number of the author's beautiful photographs taken with this monochromator ; and for many purposes where freedom from background fogging is necessary, it is particularly valuable. Chapter 7 deals with the study of crystal texture, and includes both the determination of the size of small crystals and the preferred orientation of crystals in polycrystalline aggregates. This discussion also is rather brief, and the omission of the use of charts of constant ?-, p- and ?-values is unfortunate. The absence of references to moving-film methods of studying preferred orientation also restricts the usefulness of this chapter. Chapter 8 deals with the connexion between cell dimensions and chemical composition, particularly in relation to solid solution in alloys. A short section is devoted to the measurement of internal stresses in metals by the changes in cell dimensions induced by those stresses. Chapter 9, on superlattices, leads on to a more general study of imperfections in crystals in Chapter 10. This chapter includes the study of the influence of the size of crystals, of thermal agitation and of the effects of cold-working on the breadths and intensities of powder lines. Chapter 11 deals with diffraction by liquids and amorphous bodies. The twelfth and last chapter describes another special contribution of the author to this subject, namely, the use of the scattering of X-rays at very small angles from the incident beam to determine the shape and size of the particles. This method, which is applicable to aggregates of particles ranging in size between 20 and 500 A., no matter whether they are crystalline or amorphous, is likely to yield valuable information on colloidal substances which is complementary to that which can be obtained by other X-ray methods.

Radiocristallographie

Par André Guinier. Pp. ix + 294 + 16 plates. (Paris: Libr. Dunod, 1945.) 725 francs.