Effect Of Yttrium Ion Implantation Research Articles

Impact of yttrium ion implantation on corrosion behavior of laser beam welded zircaloy-4 in sulfuric acid solution

In order to study the effect of yttrium ion implantation on the aqueous corrosion behavior of laser beam welded zircaloy-4 (LBWZr4), The butt weld joint of zircaloy-4 was made by means of a carbon dioxide laser, subsequently the LBWZr4 samples were implanted with yttrium ion using a MEVVA source at an energy of 40 keV, with a fluence range from 1 × 10 16 to 4 × 10 16 ions/cm 2 at about 150 °C. Three-sweep potentiodynamic polarization measurement was employed to evaluate the aqueous corrosion behavior of yttrium-implanted LBWZr4 in a 0.5 M H 2SO 4 solution. Scanning electron microscopy (SEM) was used to examine the surface topographic character of the yttrium-implanted LBWZr4 before and after the potentiodynamic polarization measurement. The valences of the carbon, yttrium, and zirconium in the surface layer were analyzed by X-ray photoemission spectroscopy (XPS). It was found that a significant improvement was achieved in the aqueous corrosion resistance of yttrium-implanted LBWZr4 compared with that of the un-implanted LBWZr4. The mechanism of the corrosion resistance improvement of the yttrium-implanted LBWZr4 is probably due to the addition of the yttrium oxide dispersoid into the zirconium matrix.

Oxidation of alumina formers at 1173 K: effect of yttrium ion implantation and yttrium alloying addition

The oxidation behaviour of three alumina forming FeCrAl alloys has been investigated during isothermal exposures in air at 1173 K. Two of them were Kanthal A1, differing by the presence or not of implanted yttrium. The third one, Kanthal AF contains alloying additions of yttrium. Kinetic results indicate that only yttrium implantation significantly reduces the growth rate of the oxide scale during the early oxidation stage. For longer oxidation times, the reactive element markedly influences the oxidation rate and the composition of the oxide scale, whatever its introduction mode in the alloy. In situ X-ray diffraction shows that yttrium suppresses the formation of transition alumina and promotes the growth of α-Al 2O 3, thereby leading to the earlier formation of a protective oxide scale.

Effect of yttrium ion implantation on the oxidation of alumina formers at 1173 K

L'etude de l'effet de l'implantation ionique d'yttrium sur l'oxydation isotherme d'un alliage FeCrAl commercial, le Kanthal Al, a ete conduite sous air a 1173 K. La cinetique d'oxydation de l'alliage non implante se caracterise par une prise de masse rapide au cours des six premieres heures (etape initiale transitoire) suivie par un regime d'oxydation parabolique. L'implantation modifie le comportement a l'oxydation de l'alliage qui presente alors deux regimes paraboliques consecutifs. La presence de l'element actif diminue de facon consequente la vitesse d'oxydation de l'alliage. L'implantation d'yttrium affecte egalement la composition de la couche d'oxyde. La diffraction, des rayons X in situ montre que l'yttrium supprime la formation des alumines de transition et favorise la croissance d'alumine α, ce qui ameliore le caractere protecteur de la couche d'oxyde formee.

The air oxidation of yttrium ion implanted zircaloy-4 at 500°C

The beneficial effect of yttrium ion implantation on the oxidation behavior of zircaloy-4 at 500°C has been investigated. Zircaloy-4 specimens were implanted by yttrium ions with a dose range from 1×10 16 to 1×10 17 ions/cm 2 at about 120°C, and then oxidized in air at 500°C for 100 min. The valence of the oxides in the scale was analyzed by X-ray photoemission spectroscopy (XPS). Glancing angle X-ray diffraction (GAXRD) was employed to examine the phase transformation due to the yttrium ion implantation in the oxide films. The addition of yttrium changed the phase in the scale from monoclinic zirconia to tetragonal zirconia. The measurement of weight gain showed that a significant improvement was achieved in the oxidation behavior of yttrium ion implanted zircaloy-4 compared with that of the as-received zircaloy-4. The mechanism of the improvement was discussed.

The Effect of Yttrium Ion Implantation on the High Temperature Oxidation Properties of NiAl

ABSTRACTNiAl was ion implanted with yttrium (2×1016 cm−2) in order to study its effect on the very high temperature (1000–1500°C) oxidation properties. At 1000°C, implanted Y stabilizes the faster growing θ-Al2O3 phase, thus slightly increasing the oxidation rate. At 1200°C, where predominantly α-Al2 O3 is formed with and without Y, there is a factor of 4 reduction in the oxidation rate. However at higher than 1200°C, there is little effect by Y on the oxidation rate. Cyclic testing showed that the Y implant had an imperfect and short-lived improvement on adherence relative to other Y-containing alloys. Variations in aluminum content from 23.5 to 36.0wt%(40–55at%) had little effect on the oxidation properties. Initial experiments at 1500°C with a novel Rh marker indicate that alumina grows at least partially by outward cation diffusion both with and without Y.