Zirconium to Boron

In addition to these principal alloying elements, which provide soHd solution strengthening and/or precipitation strengthening, wrought alloys may contain small amounts of titanium and boron [7440-42-8J, B, for control of ingot grain size, and ancillary additions of chromium, manganese, and zirconium to provide dispersoids. AH commercial alloys also contain iron and siUcon. 

A catalytic reduction of C02 to CH4 was described in 2006 by Matsuo et al. [100], using hydrosilanes C02 + 4 Si-H — CH4 + 4 Si-O, catalyzed by zirconium-borane complexes LZr(CH2Ph)(B(C6F5)4). These authors showed that the combination of both zirconium and boron provided the catalytic activity. In the absence of Zr, the reduction of C02 was not observed, which suggested that the coordination of C02 to the Zr center took place prior to the actual reduction. This coordinated C02 would then be more reactive towards hydrosilylation so as to yield the initial product CH2(OSiR3)2, although the nature of the counterion was also shown to be critical during the course of the reaction. 

More recently, ceramic composite materials have been described that incorporate zirconium diboride platelet reinforcements in a zirconium carbide matrix [34, 35], These materials are prepared by the directed reaction of molten zirconium with boron carbide (B4C) to form a ceramic material composed of zirconium diboride platelets in a zirconium carbide matrix with a controlled amount of residual zirconium metal. 

Several different processes can be used to produce ZrB2 , these are similar to those used to form carbides and nitrides. Commercially, either a direct reaction between zirconium and boron... 

In the system NaCl-KCl-K2ZrF6-KBF4-NaF a new process, more electropositive than the discharge of the zirconium and boron has been observed (Figure 2.). The process corresponds to a 10-electron irreversible change transfer with formation of insoluble product (ZrB2) ... 

The process of reducing carbonyl compounds (aldehydes or ketones) to alcohols is therefore known as the Meerwein-Ponndorf-Verley reaction. Although alkoxides of a number of metal(loid)s such as sodium, magnesium, titanium, zirconium, iron, boron, aluminium, tin, and antimony have been used for these reactions, those of aluminium are by far preferred, since they tend to give the minimum degree of side reactions. The use of aluminium isopropoxide over other alkoxides was also preferred by Young et al as well as by Adkins and Cox. ... 

To be classified as copper the compound must contain a minimum of 99.3% copper. Elements such as silver, arsenic, phosphorus, antimony, tel-urium, nickel, cadmium, lead, sulfur, zirconium, magnesium, boron, and bismuth may be present singly or in combination. 

Zirconium and boron phosphate Interesting results have been obtained by using this approach in order to prepare PBI composite... 

To be classified as a copper, an alloy must contain a minimum of 99.3% copper. Elements such as silver, arsenic, lead, phosphorus, antimony, tellurium, nickel, cadmium, sulfur, zirconium, manganese, boron, and bismuth may be present, singly or in combination. Because of the good electrical properties of copper, it is used primarily in electrical or electronic applications such as bus bars, waveguides, wires, switches, and transfer components. Because copper is a noble metal, it also finds many applications in corrosive environments. Table 18.4 gives the chemical composition of some of the coppers used in corrosion applications. 

When applied to boron in unalloyed zirconium, the technique proved to yield homogeneous samples and to be quantitative and repetitive within the quoted uncertainties. Only using secondary ion mass spectrometry heterogeneities could occasionally be detected in the samples with the highest boron contents (42). These were due to expected zirconium boride microprecipitations. 

The stereochemically controlled addition of organometallic species of copper, tin, silicon, palladium, zirconium, and boron to acetylenes has been investigated as a route to di-, tri-, and tetra-substituted olefins. The carbon-metal bond thus formed is cleaved in a stereoselective manner either directly, or indirectly, via the corresponding vinyl-lithium reagents with a wide variety of electrophiles. In three... 

Various metal borides can be prepared by molten salt electrolysis. Frazer et al. (1975) have deposited ZrB on nickel cathode from ZrO and B Oj dissolved in molten NajAlF at 1020°C. A graphite crucible was used as anode. A series of nickel boride diffusion compounds were also noticed by electron microprobe analysis. The ZrB deposit was found to be scaly or dendritic and was usually non-adherent. Devyatkin (2001) has also obtained ZrB on nickel cathode from cryolite- alumina melts containing zirconium and boron oxide. 

Boron, carbon and nitrogen from this polymer can not only react with the zirconium to form solids but also with the release of oxygen and hydrogen. Thermal dynamic calculations were carried out for the pyrolysis of [Zr(acac)2(C4HgO)2] and ZrB precursor with a B/Zr molar ratio of 2. Solids formed in the systems... 

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