Tungsten diborides

Although few applications have so far been found for ceramic matrix composites, they have shown considerable promise for certain military applications, especially in the manufacture of armor for personnel protection and military vehicles. Historically, monolithic ("pure") ceramics such as aluminum oxide (Al203), boron carbide (B4C), silicon carbide (SiC), tungsten carbide (WC), and titanium diboride (TiB2) have been used as basic components of armor systems. Research has now shown that embedding some type of reinforcement, such as silicon boride (SiBg) or silicon carbide (SiC), can improve the mechanical properties of any of these ceramics. 

Zirconium Diboride (ZrB2) Chromium Diboride (CrB2) Titanium mononitride (TiN) Tungsten Monocarbide (WC) Knoop lOOg 1560 kg/mm Knoop lOOg 1700 kg/mm Knoop lOOg 1770 kg/mm Knoop lOOg 1870-1880 kg/mm ... 

Figure 4.8.4 Surface microstructure of (a) tungsten carbide and (b) zirconium diboride deposited on steel samples...

The microhardness of coatings was 18-19 GPa for molybdenum carbide [6], 29-31 GPa for tungsten carbide, and 31-32 GPa for zirconium diboride. The presence of a diffusion zone that ensured the adhesion of coatings to the substrate, was confirmed by qualitative and semiquantitative X-ray spectral microanalyses of microsections which were performed with a MS-46 Cameca electronic probe. The continuity of the coating-substrate transition was confirmed by stereoscopic images of the cross-sections of the electroplated samples. 

The resistance to wear and abrasion was tested on steel 45 samples with different coatings. The second body was made of quenched steel 45. The wear resistance of samples increased by a factor of 5-7 for molybdenum carbide coatings [5], 6-9 for tungsten carbide coatings, and 8-11 for zirconium diboride coatings. 

Tungsten carbide and zirconium diboride electroplates deposited from ion melts by high-temperature electrochemical synthesis can be recommended for an increase in the surface hardness, as well as the wear, abrasive, and corrosion resistance of steel materials. 

Note TiN, titanium nitride TiC, titanium carbide B C, boron carbide Ti(CN), titanium carbonitride SiC, silicon carbide T1B2, titanium diboride AljOj, alumina WC, tungsten carbide... 

Zhang, S. C., Hilmas, G. E., Fahrenholtz, W. G. (2008). Improved Oxidation Resistance of Zirconium Diboride by Tungsten Carbide Additions. Journal of the American Ceramic Society, 97(11), 3530-3535. doi 10.1111/j.l551-2916.2008.02713.x. 

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