Zirconium amorphous

Reduction processes in which a finely powdered pigment-likc oxide is reduced at a temperature below its own melting point and that of the resultii metal furnish the so-called subsieve powders of which titanium, zirconium, amorphous boron, and hydrogen-reduced iron are the most important representatives. 

The main interest in zirconium phosphates relates to their ion-exchange properties. If amorphous zirconium phosphate is equiUbrated with sodium hydroxide to pH 7, one hydrogen is displaced and ZrNaH(P0 2 3H20 [13933-56-7] is obtained. The spacing between the zirconium layers is increased from 0.76 to 1.18 nm, which allows this phosphate to exchange larger ions. 

The corrosion behaviour of amorphous alloys has received particular attention since the extraordinarily high corrosion resistance of amorphous iron-chromium-metalloid alloys was reported. The majority of amorphous ferrous alloys contain large amounts of metalloids. The corrosion rate of amorphous iron-metalloid alloys decreases with the addition of most second metallic elements such as titanium, zirconium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, cobalt, nickel, copper, ruthenium, rhodium, palladium, iridium and platinum . The addition of chromium is particularly effective. For instance amorphous Fe-8Cr-13P-7C alloy passivates spontaneously even in 2 N HCl at ambient temperature ". (The number denoting the concentration of an alloy element in the amorphous alloy formulae is the atomic percent unless otherwise stated.)... 

Silicon hydrides, in growing amorphous silicon, 22 129-131 Silicon integrated circuits, 19 167 Siliconized coatings, 10 108 Silicon-killed free-machining steels, 24 424 Silicon lattice, 23 35 Silicon-manganese-zirconium, 26 638 Silicon microelectronics, sensor sensitivity and, 22 269... 

In this artide, we review the new field of combinatorial materials science. We describe in detail our particular materials exploration approach that we call the continuous compositional spread (CCS) approach. This CCS approach allows the synthesis and characterization of a major fraction of a ternary or pseudo-ternary phase spread in about 24 hours. We compare the CCS approach with other schemes for rapid materials investigations. We also provide an example of the successful application of the CCS approach in the discovery of a new high dielectric constant thin-film material, an amorphous zirconium tin titanate, aZTT. New combinatorial approaches to materials research can allow us to do studies that would not have been possible using conventional techniques. 

Metal alloys can be amorphous, too. LiquidmetaF alloy is an amorphous alloy of zirconium mixed with nickel, titanium, copper, and beryllium. It is used in the heads of some brands of golf clubs. Traditional metal club heads may have microscopic gaps where planes of metallic crystals meet. These tiny gaps are a potential source of weakness. The amorphous alloy is non-crystalline, so the metal structure does not have potential breakage sites. 

The rate of silicate sol and gel formation is pH and water-alcohol-sensitive as is the solubility of the amorphous silica that is formed. Silica networks are based on (Si04) " tetrahedra modified by (O3 Si-O, M+) units and often addition of boron oxide, aluminum oxide, titanium IV oxide, or zirconium IV oxide. 

Later, Yoshida et al. reported the dehydration of fructose to HMF in a batch-type reactor under subcritical water (sub-CW) and with different zirconium phosphate solid acid catalysts at 240°C (Scheme 7) [77]. Over amorphous zirconium phosphate, 80% of fructose was converted after 120 s affording HMF with a selectivity of 61%. Interestingly, no side product stemming from the rehydration of HMF was detected in this case. However, soluble polymers and furaldehyde were detected as side products. Remarkably, zirconium phosphate solid catalysts were stable under subcritical water conditions and were reused without any loss of their activity. 

Preparation and characterization of two-dimensional zirconium phosphonate derivatives in either crystalline or amorphous forms have been investigated. Two composite zirconium phosphonates in single crystal phase have also been investigated and characterized by XRD, i c-, and 3ip-MASNMR. The catalytic performance over zirconium phosphonates are evaluated by hydrolysis of ethylacetate in aqueous solution. When the composite zirconium phosphonate is composed with an acidic function and with a hydrophobic function in single crystal phase, the catalytic activity in aqueous medium showed higher activity than that of single acidic zirconium phosphonate. The composite materials become accessible to any reactant molecule and improve hydnq>hobicity. 

Addition of a soluble Zr(IV) salt to phosphoric acid results in the precipitation of a gelatinous amorphous solid. The stoichiometric crystalline zirconium phosphate can be prepared by refluxing zirconium phosphate-gel in concentrated phosphoric acid [5]. The procedures for synthesis of zirconium phosphate have been described in detail elsewhere [6]. 

Zirconium phosphonates are solid materials typically synthesized in amorphous forms under aqueous conditions by the reaction of a soluble salt of a tetravalent metal and a phosphonic acid or an organophosphoric acid ... 

Berzelius product was impure amorphous silicon. Zirconium may be obtained by an analogous process (32). 

P. T. Cleve obtained an amorphous mass—presumably of thorium perchlorate—by treating thorium sulphate in a similar way. F. P. Yenable and I. W. Smithey prepared zirconyl perchlorate by dissolving zirconium hydroxide in 30 per cent, perchloric acid with 60 per cent, acid, the hydroxide dissolves... 

Amorphous isotactic TPX was synthesized from 4-methyl-l-pentene in the presence of the zirconium complex as the catalyst of living polymerization. The catalyst is shown in Figure 4.4. 

Metallic Glasses. Under highly specialized conditions, the crystalline structure of some metals and alloys can be suppressed and they form glasses. These amorphous metals can be made from transition-metal alloys, eg, nickel—zirconium, or transition or noble metals in combination with metalloid elements, eg, alloys of palladium and silicon or alloys of iron, phosphoms, and carbon. 

Metallocene Catalysts. Higher a-olefins can be polymerized with catalyst systems containing metallocene complexes. The first catalysts of this type (Kaminsky catalysts) include metallocene complexes of zirconium such as biscyclopentadienylzirconium dichloride, activated by methylaluminoxane. These catalysts polymerize a-olefins with the formation of amorphous atactic polymers. Polymers with high molecular weights are produced at decreased temperatures and have rubber-like properties. 

The structure and nature of acidity of sulphated zirconia has been recently investigated (ref. 8-10). Untreated zirconium hydroxide which is amorphous, crystallises 1n the monoclinic form at 350°C. On the contrary, the sulphate treated zirconium hydroxide crystallises at higher temperature (500ooC) into tetragonal form, which has significantly greater surface area as compared to the monoclinic zirconia. The infra red spectra of absorbed pyridine indicate presence of only coordinatively bonded pyridine and not the protonated pyridine implying that the zirconia is predominantly of Lewis... 

It was quite unexpectedly found that the amorphous samples of zirconium and hafnium alkoxides M(OR)4 contain several types of oxocomplexes, particularly, M3O(OR)i0 and M40(0R)14 [1612], The trinuclear Zr3([l3-0)()i3-OBu XOBu ), was isolated in a crystalline form and turned out to be a structural analog of the known isopropoxide clusters of Th, Mo, and U(IV) -MjOCOPr ),) [1520] (see also Sections 4.3 and 12.12). The inclusion of the solvent molecules inside the cavities of the structures and formation of alcohol solvates in many cases leads to microanalysis data that does not deviate much from those calculated for M(OR)n. 

The addition of zirconium to activated carbon may substantially increase the removal of arsenic from water (Daus, Wennrich and Weiss, 2004 Schmidt et al., 2008). (Daus, Wennrich and Weiss, 2004) used batch and column tests to evaluate the ability of five materials (activated carbon, zirconium-loaded activated carbon, zerovalent iron, granulated Fe(III) hydroxide, and a commercial product, Absorptionsmittel 3 ) to sorb As(III) and As(V) from water. The GAC had grain sizes between 1.0 and 1.5 mm. The material was primarily chosen as a comparison with the zirconium-loaded sample. The zirconium-loaded activated carbon contained 28 mg zirconium g 1 activated carbon and was produced by shaking activated carbon in a solution of zirconyl nitrate (Zr0(N03)2). The zerovalent iron (Fe(0)) primarily had particle sizes of 1.2-1.7 mm. Absorptionsmittel 3 is a mixture of calcite, brucite, fluorite, and iron hydroxides. The granular iron hydroxides consisted of mostly amorphous Fe(III) hydroxide coatings on sand grains (particle sizes of 3-4mm) (Daus, Wennrich and Weiss, 2004, 2950). 

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