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During this time when the hot cladding is exposed to steam some oxidation of the zirconium will occur to form a zirconium oxide which is more zirconium rich than zirconia. This Zr(O) phase is the α-phase, further oxidation forms zirconia. The longer the cladding is exposed to steam the less ductile it will be.
One of the main uses of zirconium alloys is in nuclear technology, as cladding of fuel rods in nuclear reactors, especially water reactors. A typical composition of nuclear-grade zirconium alloys is more than 95 weight percent [ 1 ] zirconium and less than 2% of tin , niobium , iron , chromium , nickel and other metals, which are added to ...
Yttria-stabilized zirconia (YSZ) crystal structure. Yttria-stabilized zirconia (YSZ) is a ceramic in which the cubic crystal structure of zirconium dioxide is made stable at room temperature by an addition of yttrium oxide. These oxides are commonly called "zirconia" (Zr O 2) and "yttria" (Y 2 O 3), hence the name.
Zirconia is also employed in the deposition of optical coatings; it is a high-index material usable from the near-UV to the mid-IR, due to its low absorption in this spectral region. In such applications, it is typically deposited by PVD. [23] In jewelry making, some watch cases are advertised as being "black zirconium oxide". [24]
The most common oxide is zirconium dioxide, ZrO 2, also known as zirconia. This clear to white-coloured solid has exceptional fracture toughness (for a ceramic) and chemical resistance, especially in its cubic form. [37] These properties make zirconia useful as a thermal barrier coating, [38] although it is also a common diamond substitute. [37]
Common fuels used are titanium, titanium(II) hydride, zirconium, zirconium hydride, and boron. The size of the fuel particles is determined to produce hot particles with the required burning time. More exotic materials can be used, e.g. carboranes. [1] For special applications, pyrophoric igniters can be used which burst into flame in contact ...
This gas is compressed as the flame propagates and the pressure in the combustion chamber rises. The high pressure and corresponding high temperature of unburnt reactants can cause them to spontaneously ignite. This causes a pressure wave to traverse from the end gas region and an expansion wave to traverse into the end gas region.
A planar wideband zirconia sensor (schematic picture) A variation on the zirconia sensor, called the "wideband" sensor, was introduced by NTK in 1992 [5] and has been widely used for car engine management systems in order to meet the ever-increasing demands for better fuel economy, lower emissions and better engine performance at the same time. [6]