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Characteristics of the Metal–Metal Oxide Reaction Matrix
Published in Anthony Peter Gordon Shaw, Thermitic Thermodynamics, 2020
Titanium metal is produced by the reaction of gaseous TiCl4 with molten magnesium in a sealed reactor. The reactor walls are typically made of stainless steel, and the process must be carried out in the absence of oxygen [13]. Similar processes have been used to prepare zirconium and hafnium. Overall, the most common oxidation state of these metals is +4 although the +3 and +2 states are not uncommon for titanium. Rutile is the most common form of TiO2 and is one practical source of the metal. Another useful ore is ilmenite, FeTiO3. The compound Ti3O5 contains titanium in oxidation states +4 and +3. The compounds Ti2O3 and TiO contain the metal in the +3 and +2 oxidation states, respectively. Cubic zirconia (cubic ZrO2) has been used as a diamond simulant in inexpensive jewelry because of its high refractive index and acceptable hardness. Rutile actually has a greater refractive index, but it is softer and would not be as durable. Hafnium is found as an impurity in zirconium-bearing minerals such as zircon, ZrSiO4.
Physical Properties of Crystalline Infrared Optical Materials
Published in Paul Klocek, Handbook of Infrared Optical Materials, 2017
James Steve Browder, Stanley S. Ballard, Paul Klocek
Notes: This stabilized form of zirconium dioxide, called cubic zirconia, can be produced synthetically at room temperature by doping with Y2O3, MgO2, or CaO. This form is best known for its role in jewelry. Its refractive index and resistance to abrasion and could be useful for refractometer prisms (Wood and Nassau, Appl. Opt. 21(16), 2978, 1982).
Densification
Published in David W. Richerson, William E. Lee, Modern Ceramic Engineering, 2018
David W. Richerson, William E. Lee
Cubic zirconia single crystals have optical properties relatively close to those of diamond. This includes a high refractive index of 2.17–2.18 (compared to 2.42 for diamond) and a dispersion of 0.060 (compared to 0.044 for diamond). As a result, faceted cubic zirconia has brilliance similar to that of faceted diamond and has become an important gemstone.
Thermal efficiency enhancement using a ceramic coating on the cylinder liner and the piston head of the IC engine
Published in International Journal of Ambient Energy, 2021
P. Anand, D. Rajesh, M. Shunmugasundaram, I. Saranraj
Zirconium dioxide (ZrO2), sometimes known as zirconia (not to be confused with zircon), is a white crystalline oxide of zirconium. Its most naturally occurring form, with a monoclinic crystalline structure, is the mineral baddeleyite (Alkidas 1989). A dopant stabilised cubic structured zirconia, cubic zirconia, is synthesised in various colours for use as a gemstone and a diamond simulant. Zirconia can be found in three crystal structures and it can be seen in Figure 2. These are monolithic (m), tetragonal (t) and cubic (c) structures. The monolithic structure is stable between room temperature and 1170°C while it turns to a tetragonal structure above 1170°C. The tetragonal structure is stable up to 2379°C and above this temperature, the structure turns to cubic structure (Assanis et al. 1991).