The E911 steel grade has been developed from grade P91 to increase the creep properties at 600 oC through the control of vanadium, nitrogen and the addition of tungsten. Grade 911 shows a better creep performance than grade 91. Microstructure stability of both steels was investigated by isothermal ageing tests for up to 10,000 hours at 600 and 650 oC and their mechanical behaviour is compared. Results on welded joints have also been compared with base material.

1 GHz very high frequency acoustical imaging displays a micronic resolution. Owing to its nature of sub-surface imaging, it is well adapted to the characterization of porosity. Used as a means for quantitative measurements through acoustic signature processing, it provides sufficiently localized information to characterize the elastic properties proper to each component of a SiC/SiC minicomposite, the fiber and the matrix.

The applications of vacuum treatments for coating metals are recalled. The surface preparation, which is essential for any efficient deposition process, is first examined. The main vacuum coating techniques are described in detail, with the emphasis on technologies actually used in tndustry, with their advantages and disadvantages. Examples of the industrial application of this process are given and their economic importance discussed.