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Thin Films for Cutting Tools
Published in Fredrick Madaraka Mwema, Tien-Chien Jen, Lin Zhu, Thin Film Coatings, 2022
Fredrick Madaraka Mwema, Tien-Chien Jen, Lin Zhu
Carbides are salts composed of metals combined with carbon atoms. They have a general characteristic of high hardness values, high melting point, and good electrical and heat conductors and heat resistance. Some of the carbides used as coatings for cutting tool applications are discussed below.
Ceramics and Composites
Published in Yip-Wah Chung, Monica Kapoor, Introduction to Materials Science and Engineering, 2022
A cermet is simply a mixture of ceramics and metals, a special case of composite materials. The intent is to combine the high strength of ceramics with the high fracture toughness of metals. A good example is WC-Co. Adding 5%–10% cobalt (a tough metal) to tungsten carbide (a strong and wear-resistant ceramic) results in a tough material with excellent wear resistance under high stress. This material is known as cemented carbide and is used in cutting tools.
High-Rate Anodic Dissolution of Ti, W, and Their Carbides
Published in Madhav Datta, Electrodissolution Processes, 2020
Carbides are carbon compounded with a nonmetal (such as calcium, silicon, or boron) or metal (such as tungsten, titanium, tantalum, cobalt, or vanadium). Metal carbides are extremely hard and resistant to wear, corrosion and heat, making them excellent candidates for coatings for drills and other tools. They possess other valuable properties in combination with toughness, such as electrical conductivity, low thermal expansion, and abrasiveness.
Laser powder bed fusion as a net-shaping method for reaction bonded SiC and B4C
Published in Virtual and Physical Prototyping, 2022
Sebastian Meyers, Miquel Turón Vinãs, Jean-Pierre Kruth, Jef Vleugels, Brecht Van Hooreweder
Carbide ceramics have a number of desirable properties that make them highly suitable for various engineering applications. Two of the most widely used carbide ceramics are silicon carbide and boron carbide. Silicon carbide (SiC) is a lightweight ceramic with a high Young’s modulus, excellent corrosion resistance, a high thermal conductivity and a low thermal expansion coefficient. It is used as a structural material in high-temperature furnaces, in the automotive industry as high-performance brake discs and diesel particulate filters, in thermal management applications and in the aerospace industry for precision instrumentation, telescope mirrors or heat exchangers. Boron carbide (B4C) can be found in applications that make use of its excellent wear resistance, like nozzles for water jet cutting or grit blasting, but also as a structural material in armour and in nuclear applications such as control rods or radiation shielding.
Performance analysis of EDM electrode manufactured by direct metal laser sintering during machining of titanium alloy (Ti6Al4V)
Published in Machining Science and Technology, 2022
Anshuman Kumar Sahu, Siba Sankar Mahapatra
As mentioned earlier, the debris of tool electrode and work piece material produced during the sparking get combined with carbon produced from dissociation of dielectric fluid to form a white layer on the EDMed surface. The white layer mostly consists of oxides and carbides of metals. The white layer predominantly consists of oxides and carbides of titanium which increases the MH of the white layer on EDMed surface. MH of the white layer is directly proportional to the machining parameters such as voltage, peak current, duty cycle and pulse-on-time. This can be observed from the factorial plots shown in Figure 13. With an increase in any of these parameters, MH of white layer also increases. The reason may be assigned that increase in any of these parameters causes spark energy density to increase. The high spark energy leads to increased carbon formation by dissociation of dielectric fluid. The carbon thus formed reacts with metal elements to form metal carbides. By the usage of graphite electrode, release of carbon particles from the electrode becomes higher during sparking process leading to formation and deposition of carbides on the EDMed surface causing increase in WLT. Hence, WLT is higher in case of use of graphite electrode in comparison to copper electrode. However, WLT observed with the usage of AlSi10Mg electrode is lowest resulting in lowest MH. The observation of this study in regard to increase of MH of the white layer with increase in process parameters of EDM during machining of titanium alloy is completely in agreement with past studies (Öpöz et al., 2018; Kumar et al., 2019).
Erosion behaviour of cobalt-based coatings with different carbide contents under high-speed propellant airflow
Published in Surface Engineering, 2020
Xiangdong Men, Fenghe Tao, Lin Gan, Weiran Duan, Yue Li, Xianghua Bai
In general, many properties of the alloy are strongly related to its carbide content. For example, under wear condition, carbides in alloy act as a strengthening phase to support and protect the structure [14]. Carbide content directly affects the hardness and wear resistance of the alloy. But in the corrosive environment carbides become the initial sites for localised corrosion or dissolution and begin to fall off because the boundary of carbide is the preferred location for corrosion and dissolution [15]. As such, increasing the carbide content decreases corrosion resistance of the alloy. Similarly, the melting of eutectic formed with carbides and the cracking of the carbide itself are the main failure forms under the high-speed propellant erosion condition [13], so the erosion resistance of the alloy may also highly depend on carbide content. Research on this issue provides an effective theoretical method to improve the erosion resistance of cobalt-based alloys for their further application to gun barrels.