Recent developments in X-ray projection microscopy and X-ray microtomography applied to materials science

After a long period of sleeping, there is recently a spectacular revival of X-ray microscopy due to the progress in X-ray sources (synchrotron radiation), X-ray optics, and X-ray detectors. However most of the attempts in this field concern the use of soft X-rays to observe, with an improved resolution, biological specimens in their wet environment. In opposition to these trends, we try to demonstrate in this paper the interest of using X-ray microscopy to materials science by applying the old principle of shadow microscopy (but with modem detectors such as CCD cameras) with harder X-rays. The excellent linearity, speed of acquisition and large dynamic of CCD cameras combined to the intrinsic advantage of X-rays "to see" inside thick specimens allows one to obtain digital images (for quantification), to follow dynamic processes (such as solid /solid diffusion) and to perform 3 dimensional reconstruction of the object by X-ray microtomography. The performance of this renewed technique is indicated and illustrated by various examples.