Quaternary carbonitrides

Upon additional alloying ternary carbonitrides quaternary carbonitrides are obtained. The group 4 and 5 transition metal carbides and nitrides are completely miscible except TiN-VC and ZrN-VC. Thus, modified material properties can be obtained (see also Section 9.2). Information on the properties of these carbides are still scarce," a few data are given in Figure 13 and Table 4. 

Recent developments in the field of CVD and PVD layers are multilayer coatings that consist of carbonitrides, carbides, nitrides, and oxides, whereas the trend goes into the use of ternary and quaternary carbonitrides such as Zr(C,N) and (Ti,Hf)(C,N) as well as mixed oxides such as Al203/Ti02, Al203/Ti02/Hf02. 

Carbonitride alloys, quaternary, 17 218. See also Carbonitrides Carbon nitride entries... 

Ternary phases with structures different from those of the phases of the binary boundary systems are more the exception than the rule. Such phases have been reported in the systems Nb-Mo-N, Ta-Mo-N, Nb-Ta-N, Zr-V-N, Nb-Cr-N, and Ta-Cr-N. Information about ternary transition metal-nitrogen systems is often available for specific temperatmes only. This is even more the case for quaternary nitride systems, which play a role in the production of carbonitride cermets where quaternary compounds of the types (Ti,Mo)(C,N) and (Ti,W)(C,N) are of interest (see Carbides Transition Metal Solid-state Chemistry), as well as in layer technology where titanium nitride-based coatings of the type Ti(C,B,N) are prepared by magnetron sputtering. Layers consisting of ternary compounds of the type (Ti,Al)N and (Ti,V)N also have favorable properties with respect to abrasion resistance. 

Complex carbides containing boron, occurring frequently in boron-alloyed steels and superalloys, are also named carboborides. Metal borocarbides (see Table 1) are synthesized by powder metallurgical methods or are extracted from a metal matrix. There are pseudoternary or -quaternary borocarbides, such as Mn23(B, C) or (Cr, Mn, Fe)23 (B, C)g (t phases) although boron-carbon substitution in borocarbides is less pronounced than nitrogen-carbon substitution in metal carbonitrides. 

Polymer derived ceramics have been known for the last four decades and are prepared via solid-state thermolysis of preceramic polymers. They exhibit a unique combination of remarkable properties due to their covalent bonding and amorphous nature. Thus, silicon oxycarbide (SiOC) and silicon carbonitride (SiCN) based ternary PDCs have been shown to possess outstanding high-temperature properties such as stability with respect to crystallization and decomposition, oxidation and corrosion resistance as well as excellent thermomechanical properties (e.g., near zero steady state creep resistance up to temperatures far beyond 1000 °C). Their properties are directly influenced by the chemistry and the architecture of the preceramic precursors, thus there is an enormous potential in tuning the microstructure and properties of the PDCs by using tailored polymers. Furthermore, suitable chemical modification of the preceramic precursors leads to quaternary and multinary ceramics, as it has been shown for instance for silicon boron carbonitride ceramics in the last 25 years, which in some cases exhibit improved properties as compared to those of the ternary materials. 

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