Wetting behaviour and reactivity between liquid Gd and ZrO2 substrate

Abstract

The wetting behavior and reactivity between molten pure Gd and polycrystalline 3YSZ substrate (ZrO 2 stabilized with 3 wt% of Y 2 O 3 ) were experimentally determined by a sessile drop method using a classical contact heating coupled with drop pushing procedure. The test was performed under an inert flowing gas atmosphere (Ar) at two temperatures of 1362 °C and 1412 °C. Immediately after melting (T m =1341 °C), liquid Gd did not wet the substrate forming a contact angle of θ=141°. The non-wetting to wetting transition (θ < 90°) took place after about 110 seconds of interaction and was accompanied by a sudden decrease in the contact angle value to 67°. Further heating of the couple to 1412 °C did not affect wetting (θ=67°±1°). The solidified Gd/3YSZ couple was studied by means of optical microscopy and scanning electron microscopy coupled with X-ray energy dispersive spectroscopy. Structural investigations revealed that the wettability in the Gd/3YSZ system is of a reactive nature associated with the formation of a continuous layer of a wettable reaction product Gd 2 Zr 2 O 7 .

The effect of testing procedure on DSC measurements of Gd-Ti-Zr alloy using ZrO2 container

“…Moreover, the ZrO2 container did not change its initially white color during high temperature measurements and prolonged contact with molten alloy. This is additional evidence for the presence of oxidizing conditions in test #1, because it is well-known that at high temperature and under non-oxidizing conditions ZrO2 is easily transformed to non-stoichiometric ZrO2-x with an accompanying change in color from white to black [8][9][10].…”

“…In contrast to test #1, the initially white ZrO2 container has changed its color to a light gray (test #2) or dark gray (test #3). This phenomenon is typical for oxides of transition metals MeO2 (Me -Zr, Ti, Hf) and is due to the loss of oxygen and the formation of non-stoichiometric oxides MeO2-x, when heated in a non-oxidizing atmosphere [8][9][10]. Thus the above observations give an experimental evidence that in tests #2 and #3, the amount of oxygen in the chamber was significantly lower than in test #1, which is in agreement with the different testing procedures applied (i.e.…”

High-Temperature Interaction of Liquid Gd with Y2O3

“…In the available literature, there is no information on a chemically stable material that could be used for hightemperature contact with gadolinium, although quite different refractories have been reported to be used in the works where Gd-rich alloys or Gd-containing compounds were synthesized or examined at high temperatures using container-assisted methods (Ref [1][2][3][4][5][6][7][8][9]. Waring .…”