Zirconium oxide zirconia

Glass Tanks Glass tank linings, made of ceramics, should withstand the molten reactive glass apart from the high temperature involved. They are made up of zirconium oxide (zirconia) or a mixture of zir-conia, alumina, and silica. 

Another important binary ceramic system is that for zirconium oxide (zirconia) and calcium oxide (calcia) a portion of this phase diagram is shown in Figure 12.24. The horizontal axis extends to only about 31 wt% CaO (50 mol% CaO), at which composition the compound CaZr03 forms. It is worth noting that one eutectic (2250°C and 23 wt% CaO) and two eutectoid (1000°C and 2.5 wt% CaO, and 850°C and 7.5 wt% CaO) reactions are fonnd for this system. 

Figure Bl.25.9(a) shows the positive SIMS spectrum of a silica-supported zirconium oxide catalyst precursor, freshly prepared by a condensation reaction between zirconium ethoxide and the hydroxyl groups of the support [17]. Note the simultaneous occurrence of single ions (Ff, Si, Zr and molecular ions (SiO, SiOFf, ZrO, ZrOFf, ZrtK. Also, the isotope pattern of zirconium is clearly visible. Isotopes are important in the identification of peaks, because all peak intensity ratios must agree with the natural abundance. In addition to the peaks expected from zirconia on silica mounted on an indium foil, the spectrum in figure Bl. 25.9(a)...

Zincite, see Zinc oxide Zincosite, see Zinc sulfate Zincspar, see Zinc carbonate Zirconia, see Zirconium oxide... 

Similarly, fusion of milled zircon with dolomite or lime forms CaSiO and MgZrO [12032-31 -4] CaZrO [12013-47-7] and CaO Ca2SiO or CaSiO and Zr02, and is used to prepare zirconium oxide, usually as calcia-stabiUzed cubic zirconia because of the calcia left in soHd solution in the zirconia (27-29). 

Zirconium oxide is fused with alurnina in electric-arc furnaces to make alumina—zirconia abrasive grains for use in grinding wheels, coated-abrasive disks, and belts (104) (see Abrasives). The addition of zirconia improves the shock resistance of brittle alurnina and toughens the abrasive. Most of the baddeleyite imported is used for this appHcation, as is zirconia produced by burning zirconium carbide nitride. 

Zirconium oxide is used in the production of ceramic colors or stains for ceramic tile and sanitary wares. Zirconia and siHca are fired together to form zircon in the presence of small amounts of other elements which are trapped in the zircon lattice to form colors such as tin—vanadium yellow, praseodymium—zircon yellow [68187-15-5] vanadium—zircon blue [12067-91 -3] iron—zircon pink [68412-79-3] indium—vanadium orange (105—108). 

Zifkon, n, zirconium zircon, -brenner, m, zirconium (incandescent) filament, -erde, /, zirconia, zirconium oxide. -glas, n. zir conium glass. 

The dehydration of 1-hexanol to hexene was conducted over heterogeneous sulfated zirconium oxide catalyst [19, 138]. The zirconia was treated with sulfuric acid and is known as super acid catalyst, having well documented performance for many reactions [19]. The reaction conditions are notably milder as for other acid catalysts, such as silica-alumina. 

The oxidation-resistant SiC fiber was prepared from polycarbosilane containing Zr(OC4H9)4 by the same process as that used for the aforementioned tita-nia/silica fiber, except that the calcination was performed in Ar atmosphere at 1400 °C. In this case, the polycarbosilane and Zr(OC4H9)4 were effectively converted into SiC-based bulk ceramic and zirconium oxide (cubic zirconia). Before the conversion, bleed-out of the zirconium compound proceeded effectively. AES depth analysis of the fiber surface showed an increase in the concentration of zirconium towards the surface. This construction was confirmed by the TEM image of the cross-section near the fiber surface. This indicates the direct production of a SiC-based fiber covered with a Zr02 surface layer, which... 

Zirconium oxide (ZrO ) is the most common compound of zirconium found in nature. It has many uses, including the production of heat-resistant fabrics and high-temperature electrodes and tools, as well as in the treatment of skin diseases. The mineral baddeleyite (known as zirconia or ZrO ) is the natural form of zirconium oxide and is used to produce metallic zirconium by the use of the Kroll process. The KroU process is used to produce titanium metal as well as zirconium. The metals, in the form of metaUic tetrachlorides, are reduced with magnesium metal and then heated to red-hot under normal pressure in the presence of a blanket of inert gas such as helium or argon. 

Stabilized zirconia refers to a solid solution of zirconium oxide with one or more of a number of stabilizing oxides (CaO, MgO, 20, or others) to form a cubic fluorite structure. This... 

More recently, the reactivity of SZ has been assigned to its oxidizing ability,129-131 which should not be surprising because it has often been considered as SO3 adsorbed on zirconium oxide. However, that sulfated zirconia is not only an oxidant but also a strong protic acid has been demonstrated by Sommer, Walspurger, and co-workers132 on the basis H/D exchange experiments with neopentane. 

The manufacturer of ceramic screwdrivers - JAWA - has developed a high-quality, reasonably priced screwdriver. It is made of zirconia (zirconium oxide) ceramics, which is harder and more durable than ordinary ceramics. 

Both aluminum oxide and zirconium oxide are catalytically interesting materials. Pure zirconium oxide is a weak acid catalyst and to increase its acid strength and thermal stability it is usually modified with anions such as phosphates. In the context of mesoporous zirconia prepared from zirconium sulfate using the S+X I+ synthesis route it was found that by ion exchanging sulfate counter-anions in the product with phosphates, thermally stable microporous zirconium oxo-phosphates could be obtained [30-32]. Thermally stable mesoporous zirconium phosphate, zirconium oxo-phosphate and sulfate were synthesized in a similar way [33, 34], The often-encountered thermal instability of transition metal oxide mesoporous materials was circumvented in these studies by delayed crystallization caused by the presence of phosphate or sulfate anions. 

Ceisla U., Froba M., Stucky G., Schiith F., Flighly ordered porous zirconias from surfactant-controlled syntheses Zirconium oxide-sulfate and zirconium oxo phosphate, Chem. Mater. 11 (1999), 227-234. 

Zirconium oxide has also been used as a substrate by itself. Researchers at Cornell University evaporated some of the yttrium superconductor with beams of high-energy electrons, deposited the vapors onto bits of the zirconia, and then etched a circuit pattern a fraction of an inch long. Not only did the superconductor film carry current of around 1,000,000 amps per square centimeter, but it conducted electrical impulses as brief as ten to fifteen-trilli-onths of a second without distortion—impossible with conventional materials—and at very high levels of current. Those incredibly short pulses raise the distinct possibility that an enormous amount of electronic data, not only in a computer but in a telephone line as well, can be transmitted via the new superconductors at ultrafast speeds. 

The dynamic membranes originally developed by Union Carbide are protected by three core patents U.S, 3977967, 4078112, and 4412921 (Trulson and Litz, 1976 Bibeau, 1978 and Leung and Cacciola, 1983) and their foreign equivalents. Those patents cover a broad range of metal oxides such as zirconia, gamma alumina, magnesia>alumina spinel, tantalum oxide and silica as the membrane materials and carbon, alumina, aluminosilicates, sintered metals, fiberglass or paper as the potential porous support materials. However, their marketed product, trade named Ucarscp membranes, focused on dynamic membranes of hydrous zirconium oxide on porous carbon support. 

---