Hard metal cutting tools

Silicon carbide (SiC), nearly as hard as diamonds, is used as an abrasive in grinding wheels and metal-cutting tools, for lining furnaces, and as a refractory in producing nonferrous metals. 

USE To increase hardness, toughness, elasticity, and tensile strength of steel manuf alloys manuf filaments for incandescent lamps and in electron tubes in contact points for automotive, telegraph, radio and television apparatus in phonograph needles. Tungsten carbides W C. WC) used in rock drills, metal-cutting tools, wire-drawing dies. WC used as catalyst instead of platinum Bennett et at.. Science 184, 563 (1974). 

Alumina is uniquely suited for metal cutting tools due to its chemical inertness and high hot hardness at the temperatures typically reached in these applications (Quinto 1988). In addition to... 

Titanium Nitride. TiN a special refractory material m.p. approx. 3000°C thermal expansion (25-1400°C) 9 x lO- . It can readily be produced from TiC and NH3. TiN coatings on metal cutting tools act as a diffusion barrier to impurities. They have higher electrical conductivity and better adhesion than alumina, and are used as an undercoat for AI2O3 coatings on tungsten carbide. Thin TiN films show iridescent interference effects, and are used as decorative hard surfacing for watches and jewelry. 

Tool steels are high carbon steels (up to about 1 wt % C) that contain appreciable amounts of tungsten or molybdenum. These elements increase the ability of a tool steel to retain its hardness to relatively high temperature. This property is important since most metal cutting tools... 

Cheapest of all are the particulate composites. Aggregate plus cement gives concrete, and the composite is cheaper (per unit volume) than the cement itself. Polymers can be filled with sand, silica flour, or glass particles, increasing the stiffness and wear-resistance, and often reducing the price. And one particulate composite, tungsten-carbide particles in cobalt (known as "cemented carbide" or "hard metal"), is the basis of the heavy-duty cutting tool industry. 

The use of tungsten carbide alloyed with cobalt, well known as Hard Metal is used for cutting tools because of its excellent wear resistance but finds little use as a corrosion resistant material. 

Evaporation is used extensively for the deposition of aluminum and other low melting-point metals as well as hard coatings such as TiN for cutting tools, decorative coatings (jewelry), and for the metallization of paper and fibers. It is also a major coating... 

Titanium Carbide. Carbides of transition metals are known for their hardness, wear resistance and also for their high electrical conductivity, which makes them attractive as a refractory coating material for cutting tools or bearings. Only little work has been done on the electrochemical stability of transition metal carbides with the exception of TiC, where a corrosion and passivation mechanism was suggested by Hintermann et al. [119,120]. This mechanism was confirmed on amorphous TiC produced by metal-... 

Vanadium carbide (VC) is used to alloy iron to produce high-speed, high-temperature cutting tools for cutting metals and other hard substances. 

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