Abstract: {sup 16}O{sub 2} ({sup 18}O{sub 2}) adsorption on well-outgassed and partially reduced cerium oxide has been investigated by Fourier transform infrared spectroscopy (FT-IR) in the temperature range 200-373 K. Superoxide species (O{sub 2}{sup {minus}}{sub ads}) with a pair of characteristic bands at 1126 (1063) and 2237 (2112) cm{sup {minus}1} were detected from oxygen adsorption on both surfaces of well-outgassed and partially reduced cerium oxide. One additional band at 883 (835) cm{sup {minus}1} attributed to peroxide species (O{sub 2}{sup 2{minus}}{sub ads}) was observed together with the bands at 1129 and 2238 cm{sup {minus}1} after oxygen adsorption on partially reduced cerium oxide. The formation of these dioxygen species is strongly dependent on the pretreatment of cerium oxide. It is concluded that the superoxide species is mainly generated on a coordinatively unsaturated cerium ion while the peroxide species were formed on a pair of surface cerium ions with lower oxidation state created by reduction.

Abstract: This invention relates to a catalytic composite for treating an exhaust gas to minimize the hydrogen sulfide content thereof and comprising a first support which is a refractory inorganic oxide having dispersed thereon at least one noble metal component and having dispersed immediately thereon an overlayer comprising at least one oxygen storage component and optionally a second support which is a refractory inorganic oxide. The first support may be selected from the group consisting of alumina, silica, titania, zirconia and aluminosilicates with alumina being preferred. The noble metal component may be selected from the group consisting of platinum, palladium, rhodium, ruthenium and iridium. The oxygen storage component is an oxide of a metal which includes cerium, iron, nickel, cobalt lanthanium, neodymium, praseodymium, etc. and mixtures thereof. Cerium oxide is a preferred oxygen storage component. The second support may be selected from the group consisting of alumina, silica, titania, zirconia and aluminosilicates, with alumina preferred.

Abstract: We report the preliminary results of our study of the thermal decomposition of Ce(OC t Bu 3 ) 3 and [LiOC t Bu 3 ] n to the corresponding M(OCH t Bu 2 ) n derivatives (M=Ce, Li)

Abstract: This invention relates to an improved catalytic composite for treating an exhaust gas comprising a first support which is a refractory inorganic oxide, having dispersed thereon at least one oxygen storage component and at least one noble metal component and having dispersed immediately thereon an overlayer comprising lanthanum oxide and optionally a second support which is a refractory inorganic oxide. The first and second support may be selected from the group consisting of alumina, silica, titania, zirconia and aluminosilicates with alumina being preferred. Additionally, the noble metal component may be selected from the group consisting of platinum, palladium, rhodium, ruthenium and iridium. The oxygen storage component is an oxide of a metal which includes cerium, iron, nickel, cobalt lanthanum, neodymium, praesodymium, etc. and mixtures thereof. This invention also relates to a process for treating automotive exhaust comprising contacting the exhaust with the catalytic composite described above. The catalytic composite shows improved activity, especially for eliminating NOx, after extensive durability testing and also minimizes the formation of H2S.

Abstract: An exterior porous electrode (10), bonded to a solid oxygen ion conducting electrolyte (13) which is in contact with an interior electrode (14), contains coarse metal particles (12) of nickel and/or cobalt, having diameters from 3 micrometers to 35 micrometers, where the coarse particles are coated with a separate, porous, multiphase layer (17) containing fine metal particles of nickel and/or cobalt (18), having diameters from 0.05 micrometers to 1.75 micrometers and conductive oxide (19) selected from cerium oxide, doped cerium oxide, strontium titanate, doped strontium titanate and mixtures thereof.

Abstract: Phosphate laser glass compositions which include erbium ions as the active laser ion material. In one aspect, ytterbium, chromium and cerium ions are present as auxiliary dopants. The ytterbium, chromium and cerium additives serve to sensitize the erbium-doped phosphate glasses of the present invention. The glasses are particularly useful in applications where an "eye-safe" wavelength is desirable.

Abstract: The presence of trace amounts of sulphur causes an adverse effect on the oxidation behaviour of NiCrAl alloys. The deleterious effect can be checked by the addition of active elements such as yttrium, cerium or hafnium. It was found that yttrium was the most effective in combating the negative effect caused by the presence of sulphur. It was also found that an optimum amount of active element is required in order to get the best effect. This is in contrast to the sulphur-free samples where the oxidation behaviour is not critically dependent on the amount of active element. The main effect of active-element additions is a change in the composition of the scale in the initial stages of oxidation. The difference in the mechanism of active-element additions in a sulphur-containing alloy is compared with that of the sulphur-free alloy.

Abstract: Disclosed are zirconia ceramics superior in mechanical strength, hardness and toughness and a method for producing them. The zirconia ceramics contain ca. 7-12 mol % of cerium oxide and ca. 2-7 mol % of magnesium oxide and have an average crystal grain size of crystal grains thereof of 1 μm or less, at least ca. 80 mol % of the crystal grains being tetragonal grains and the balance being monoclinic grains, and have a bending strength of at least 100 kg/mm 2 , a fracture toughness of at least 10 MNm -1 .5 and a Vickers hardness of at least 1000 kg/mm 2 . The method comprises calcining a hydrate obtained by coprecipitation method from water-soluble salts of cerium and magnesium and a basic salt of zirconium or a hydrate obtained by adding water-soluble salts of cerium and magnesium to a zirconium hydrate and neutralizing the mixture of hydrates, further grinding the calcined hydrate to obtain zirconia powders of 1 μm or less in average crystal grain size, then shaping the powders and sintering the resulting shaped product.

Abstract: The corrosion-resistance of aluminum-based alloys and metal-matrix composites can be increased by treatment with cerium compounds. Immersion in a 1000 ppm solution of CeCl/sub 3/ for periods of several days has been shown to increase the pitting potential and reduce the corrosion rate. Such treatment is considered as an alternative to the use of chromate conversion coatings. It is proposed that the cerium oxide/hydroxide creates a barrier to the reduction of oxygen stifling cathodic reaction with a corresponding reduction in corrosion rate and open circuit potential. The authors' study is described.

Abstract: The effect of sputtered ceria coatings (0.2–30 nm thick) on the oxidation of Fe25Cr alloys at 1100 °C has been studied using the 18 O/secondary ion mass spectrometry technique. Samples were oxidized either in 16 O 2 only or sequentially first in 16 O 2 and then in 18 O 2 for periods up to 20 h. Oxidation rates were reduced with increasing ceria thickness up to 4 nm; there was no significant further reduction in rate for thicknesses of 4 nm or more. The secondary ion mass spectrometry sputter profiles indicated that scales were mainly Cr 2 O 3 ; iron was present in the outer part of the oxide layer at levels of 1% or less. With increasing ceria coating thickness the maximum in the cerium sputter profile moved from the vicinity of the alloy-oxide interface towards the gas-oxide interface. When Fe25Cr was sequentially oxidized, 18 O was found to have diffused towards the alloy-oxide interface. The secondary ion mass spectrometry data suggest that when ceria is located within the scale there has been a change in mechanism from predominantly cation to predominantly anion diffusion.

Abstract: A surface treatment chemical for aluminum or its alloy comprising 10-1000 parts by weight of vanadium or cerium ion, 10-500 parts by weight of zirconium ion, 10-500 parts by weight of phosphate ion and 1-50 parts by weight of effective fluorine ion. A surface treatment bath for aluminum or its alloy comprising 10-1000 ppm of vanadium or cerium ion, 10-500 ppm of zirconium ion, 10-500 ppm of phosphate ion and 1-50 ppm of effective fluorine ion, and having pH of 2.0-4.0.

Abstract: We describe a new method for light microscopic demonstration of alkaline phosphatase (ALP) activity in plastic-embedded sections. Rat tissues were fixed in acetone (-20 degrees C), infiltrated in glycol methacrylate (GMA), and embedded at 0 degrees C. Sections were cut at 1 and 2 microns, dried at room temperature, and incubated in the conventional Gomori medium. Cerium chloride was used to convert calcium phosphate into cerium phosphate, which was subsequently converted into cerium perhydroxide. The slight yellow precipitate of cerium perhydroxide was amplified using 3,3'-diaminobenzidine tetrahydrochloride (DAB). For comparison, tissue sections were processed according to the calcium-cobalt method. The method described combines exact localization of ALP activity with optimal preservation of tissue morphology.

Abstract: The extraction of neodymium from didymium nitrate solution (a mixture of 83% Nd, 15% Pr and 2% other rare earths) by quaternary amine (Aliquat 336) was studied in a 45-stage tube-type mixer-settler. Six different banks in the system were used for solvent pretreatment, neodymium-stripping, feed-loading, neodymium-loading, NdPr partition and protactinium-stripping. The organic phase containing 0.6 M Aliquat 336 was equilibrated with NH4NO3 solution before entering the neodymium-loading bank, then partially fed to NdPr partition bank after extracting neodymium ions from aqueous solution, which contained diethylenetriamine pentaacetic acid as chelating agent. The other part of organic phase loaded with neodymium ions was stripped with dilute HNO3, and 95% of the neodymium with high purity (>99%) was recovered. In the praseodymium stripping bank, about 80% protactinium mixed with cerium, lanthanum and neodymium was obtained in aqueous solution.