China 
Africa 
Explore chapters and articles related to this topic
High Alloy Steels
Published in P. C. Angelo, B. Ravisankar, Introduction to Steels, 2019
Carbon is the element that increases both hardness and hardenability and thus increases abrasion (wear) resistance. Carbon is the cheapest alloying element in tool steels. Chromium increases hardenability, wear resistance by forming carbides and corrosion resistance by forming chromium oxide layer. Chromium also increases resistance to molten metal and oxidation useful in making die steels for melting low temperature metals such as aluminium. It also increases scaling resistance. Five percent chromium can resist scaling up to 650°C, 8% chromium is required for scaling resistance up to 750°C. About 10–12% chromium is required to resist temperature of 850°C. Addition of Si (0.8–1%) increases strength of chromium oxide layer and can further increase the resistance to oxidation and scaling. Chromium also protects from chemical attack and liquid metal attack. Vanadium and molybdenum form primary carbides and act as grain refiners apart from increasing hardenability. Silicon increases hardenability and high temperature strength. Nickel increases hardenability and toughness and imparts shock resistance to tool steels and reduces cracking while quenching by decreasing austenitizing temperature. Cobalt improves red hardness (or) hot hardness (resistance to thermal softening) but it decreases hardenability. Normally, reduction in hardenability due to cobalt is compensated by adding other alloying elements that increase hardenability. Tungsten apart from forming primary carbides improves hot hardness.
Densification
Published in David W. Richerson, William E. Lee, Modern Ceramic Engineering, 2018
David W. Richerson, William E. Lee
Molten-particle spray techniques have been used extensively to deposit wear-resistant and chemically resistant coatings on a wide variety of metal and ceramic products. One interesting example is the spraying of chromium oxide (Cr2O3) on the propeller shafts of large seagoing ships. Chromium oxide greatly reduces erosive wear, provides a good surface to seal against (after surface grinding to achieve a suitable surface finish), and inhibits seawater corrosion.
Effect of counter body on wear behavior of plasma-sprayed TiO2-45Cr2O3 coating.
Published in Journal of Asian Ceramic Societies, 2021
Chromium oxide (Cr2O3) coating is used as a protective coating material in many engineering applications due to its high resistance to wear, corrosion, and oxidation. However, its fracture toughness is relatively lower than some oxide-content ceramic coatings [8]. Therefore, Cr2O3 spray powder is blended with relatively soft oxide ceramics to increase the toughness of the coating. It was reported in some studies that the addition of titanium oxide (TiO2) to Cr2O3 coating powder resulted in higher fracture toughness and wear resistance [9,10]. Berger et al. [11] studied friction and wear behavior of the Cr2O3-25TiO2 coating under dry sliding wear conditions. They reported that the friction coefficient was decreased with increasing sliding velocity. Li et al. [12] investigated the effect of TiO2 addition in different ratios on friction behavior of the Cr2O3–TiO2 coating.
Evaluation of three different glassy composites (quinary matrix designed using Cr2O3/Na2O/MnO2) in respect of radiation shielding behaviors
Published in Radiation Effects and Defects in Solids, 2021
Ozan Toker, Bayram Bilmez, Melis Ö. Toker, H. Birtan Kavanoz, Özgür Akçalı, Mehmet Yılmaz, Orhan İçelli
One of the main compounds, chromium oxide (Cr2O3) is a very suitable material since it is highly refractory, can easily be formed into any desired shape, has a high heating capacity due to its color being green, and its mechanical strength is quite satisfactory for various applications (12–14). The addition of Cr2O3 generally increases the dielectric constant of the glass. The correlation between the dielectric constant and the gamma-ray shielding was reported by (15).