Zirconium addition

G. Burrafato, A. Gaumeri, T. P. Lockhart, and L. Nicora. Zirconium additive improves field performance and cost of biopolymer muds. In Proceedings Volume, pages 707-710. SPE Oilfield Chem Int Symp (Houston, TX, 2/18-2/21), 1997. 

C-M bond addition, for C-C bond formation, 10, 403-491 iridium additions, 10, 456 nickel additions, 10, 463 niobium additions, 10, 427 osmium additions, 10, 445 palladium additions, 10, 468 rhodium additions, 10, 455 ruthenium additions, 10, 444 Sc and Y additions, 10, 405 tantalum additions, 10, 429 titanium additions, 10, 421 vanadium additions, 10, 426 zirconium additions, 10, 424 Carbon-oxygen bond formation via alkyne hydration, 10, 678 for aryl and alkenyl ethers, 10, 650 via cobalt-mediated propargylic etherification, 10, 665 Cu-mediated, with borons, 9, 219 cycloetherification, 10, 673 etherification, 10, 669, 10, 685 via hydro- and alkylative alkoxylation, 10, 683 via inter- andd intramolecular hydroalkoxylation, 10, 672 via metal vinylidenes, 10, 676 via SnI and S Z processes, 10, 684 via transition metal rc-arene complexes, 10, 685 via transition metal-mediated etherification, overview,... 

Ceria-zirconia nanophases were synthesied by a surfactant-assisted method. The refined structural data concerning the crystallite size, lattice parameters, structural microstrain, cationic occupy number and cationic defect concentration are reported. Zirconium addition into the cubic structure of ceria inhibits crystal sintering but leads to structure distortion. Different CO-metal bonds are formed when CO chemisorbs on Pd-loaded CesZr. x02 catalysts. Catalytic tests reveal that the lower zirconium content benefits the CO oxidation. 

Nanosized ceria-zirconia materials with improved thermal stability can be prepared by using the surfactant-assisted method. Structural refinements confirm that the nanocrystals contain structural microstrain and cationic lattice defects. Zirconium addition to ceria supresses the crystal sintering and imporves the thermal stability but leads to structure distortion. Both catalytic tests and CO-chemisorption show that Pd supported ceria-zirconia nanoparticles are active for CO oxidation. 

All BET surface areas are reported in Fig. 5. Whatever the series, introduction of Pr results in a decrease of the BET surface area. For series 1 samples, this decrease is even more pronounced for x > 0.5. It seems that the presence of Pr60u could be responsible for this decrease of surface area. Furthermore, the presence of zirconium remains crucial to stabilize cerium-praseodymium oxides BET surface areas of series 1 samples are much higher than those of series 2, except for x = 1. Praseodymium can stabilize the texture of ceria but its influence in obtaining high surface area oxides appears to be much weaker than in the case of zirconium addition. [2-4, 16]... 

Incorporation of an allylic substituent introduces an additional degree of complexity, in that rearrangement affords /Z-product mixtures. For example, rearrangement of the cyclohexyl substituted amide 38 affords primarily the -product, (2S)-(E)-39, with 35% cc, in addition to 27% of the Z-stereoisomcrs82. As expected, the presence of a zirconium additive shifts the product ratio in favor of the Z-product, (25)-(Z)-39. at a comparable level (74% de) of induced diastereoselection. 

Fig. 3. Effect of zirconium additions on ac losses of NbsSn at4K.

The stress corrosion cracking behaviour of X-750 can be considerably increased by a heat treatment at 760 °C/96 h in combination with improved strength, as tests in high purity water with pH 10 at 360 °C have shown [164]. As well, zirconium additions to the alloy improve the resistance to stress corrosion cracking, since the y ... 

Ti-15Mo-5Zr is a metastable type alloy that exhibits good cold fonnability and age hardenabil-ity. It is P stabilized by molybdenum to enhance corrosion resistance to reducing atmospheres. Zirconium is added to (1) enhance corrosion resistance above the level achieved by molybdenum, (2) suppress (D transformation to prevent embrittlement, and (3) to improve thermal stability of the P phase. Zirconium additions of 5% Tniniminn are used to enhance thermal stability. 

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