Cutting tools coating

These problems concerning a micron-scale deposit and an in volume substrate have rarely been studied in the past. However, from a survey of literature on cases other than that of SiC on steel, it was found that one or several interlayers may change the stress levels in the ceramic. Moreover, once a critical thickness has been reached, these interlayers have a beneficial effect. Some work has been carried out on TiN/ SiC layers on a variety of substrates. However, in all these studies, information on mechanical stability is fairly limited. Concerning the PECVD of SiC on cutting tools coated with TiN, adherence variations in relation to pretreatment processes were reported. ... 

Diamond Coating for cutting tools, coatings for wear resistance, optical coatings, semiconductor devices. 

Cutting tool Coated carbide end mill, diameter 10 mm... 

Hafnium carbide [12069-85-1] can be used as surface coating on cemented-carbide cutting tools, shows promise as a stable field emission cathode... 

Refractory compound coatings of carbides, nitrides, and oxides on cemented carbide cutting tools, mainly by the CVD process, are estimated at 300 X 10 annually worldwide. 

A wide range of cutting-tool materials is available. Properties, performance capabilities, and cost vary widely (2,7). Various steels (see Steel) cast cobalt alloys (see Cobalt and cobalt alloys) cemented, cast, and coated carbides (qv) ceramics (qv), sintered polycrystalline cubic boron nitride (cBN) (see Boron compounds) and sintered polycrystalline diamond tbin diamond coatings on cemented carbides and ceramics and single-crystal natural diamond (see Carbon) are all used as tool materials. Most tool materials used in the 1990s were developed during the twentieth century. The tool materials of the 1990s... 

Fig. 14. A scanning electron micrograph of a diamond coating on a siUcon nitride cutting tool (b) at higher magnification, the octahedral growth of...

Another approach is to coat the cutting tool material with a carbide former, such as titanium or siUcon or their respective carbides by CVD and deposit diamond on top of it. The carbide layer may serve as an iaterface between diamond and the cemented carbide, thus promoting good bonding. Yet another method to obtain adherent diamond coatings is laser-iaduced microwave CVD. By ablating the surface of the substrate with a laser (typically, ArF excimer laser) and coating this surface with diamond by microwave CVD, it is possible to improve the adhesion between the tool and the substrate. Partial success has been achieved ia this direction by many of these techniques. 

Interstitial Compounds. Tungsten forms hard, refractory, and chemically stable interstitial compounds with nonmetals, particularly C, N, B, and Si. These compounds are used in cutting tools, stmctural elements of kilns, gas turbines, jet engines, sandblast nozzles, protective coatings, etc (see also Refractories Refractory coatings). 

Garbonitrides. Use of carbonitrides in metal cutting tools, both Ti(C,N) coatings (18) and Ni—Mo cemented carbonitrides (19), is expected to increase in the 1990s. 

The largest uses of platinum group metals in electronics are ruthenium for resistors and palladium for multilayer capacitors, both applied by thick film techniques . Most anodes for brine electrolysis are coated with mixed ruthenium and titanium oxide by thermal decomposition . Chemical vapour deposition of ruthenium was patented for use on cutting tools . 

Two maj or areas of application of CVD have rapidly developed in the last twenty years or so, namely in the semiconductor industry and in the so-called metallurgical-coating industry which includes cutting-tool fabrication. CVD technology isparticularly important in the production of semiconductors and related electronic components. Itisby far the most... 

Hot-Wall Reactors. A hot-wall reactor is essentially an isothermal furnace, which is often heated by resistance elements. The parts to be coated are loaded in the reactor, the temperature is raised to the desired level, and the reaction gases are introduced. Figure 5.6 shows such a furnace which is used for the coating of cutting tools with TiC, TiN, and Ti(CN). These materials can be deposited alternatively under precisely controlled conditions. Such reactors are often large and the coating of hundreds of parts in one operation is possible (see Ch. 18). 

Figure 5.6. Production CVD reactor for the coating of cutting tools.

Experimental TiB2 coatings for cemented carbide cutting tools and other wear- and erosion-resistant applications (pumps, valves, etc.). ]... 

Coatings play a vital part in the cutting-tool industry and this is where CVD technology has made some of its most important gains. As an example, CVD films of titanium carbide on cemented carbide tools were first commercialized in the early 1960s and their use has continuously increased ever since. Today, the percentage of tools that are coated by either PVD or CVD depends on the type of tool as shown in Table 18.1 (in 1996). 

Both CVD and PVD are used extensively in the production of coatings for cutting-tool applications. The PVD processes include mag-... 

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