Zircaloy-4 cladding has been oxidized in autoclave at 633 K with various chemistry conditions ([Li+] = 0, 10, 70, 700 ppm and [B] = 0, 650 ppm as boric acid) to quantify the effect of lithium hydroxide and boric acid on the oxidation kinetics and to provide oxide films that have been analyzed by SIMS, SEM, and RAMAN spectroscopy to improve our knowledge of the oxidation process in a lithiated environment. Additional specific tests consisting of isotopic exchanges (6Li+/7Li+) have also been conducted to study the incorporation of lithium in the oxide films. The main results are that: • Depending on the water chemistry, the lithium hydroxide has two effects on the oxidation kinetics: a decrease of the time to transition and a strong enhancement of the post-transition oxidation rate. • The boric acid strongly reduces these two effects of lithium hydroxide. • In the oxide film, the lithium is located mainly in the pores (or adsorbed on their walls). • The lithium has a quick access to the bulk of the oxide film, even in the inner barrier layer (considered as not completely impervious). • The enhancement of the oxidation rate due to lithium hydroxide is linked to the degradual alteration of the inner barrier layer, up to its quasi-disappearance. These experimental results are described extensively, and several factors involved in the alteration of the inner barrier layer, such as lithium pickup in the ZrO2 film, evolution of the morphology of the oxide grains, tetragonal zirconia phase transformation, and hydriding, are then discussed.

Fast electron pattern generator (FEPG) is a variable shaped beam lithographic system specially designed for direct writing on wafers and for mask fabrication. Experimental results are given: gold gratings on silicon patterned with 10×0.3 μm spots, 1 μm gate field-effect transistor (FET), masks 1×. All these results performed with a 5 A/cm2 current density are consistent with a 1 μm technology. When the spot current exceeds 5 A/cm2, defects due to the space charge effect appear. Thermal effects on glass substrates are pointed out.

No abstract

No abstract

No abstract