The Analysis of Resistance to Brittle Cracking of Tungsten Doped TiB2 Coatings Obtained by Magnetron Sputtering

Abstract

In this work, the authors present the possibility of characterization of the fracture toughness in mode I (KIC) for TiB2 and TiB2 coatings doped with different concentration of W (3%, 6% and 10%). The Young’s modulus, hardness and fracture toughness of this coatings are extracted from nanoindentation experiments. The fracture toughness was evaluated using calculation of crack length measurement. An important observation is that increasing tungsten concentration in the range 0–10% changes the microstructure of the investigated coatings: from columnar structure for TiB2 coating to nano-composite structure for Ti-B-W (10%) coating. It can be concluded that doping with concentration 10 at.% W causes an increase of the fracture toughness for the tested coatings.

Influence of W Addition on Microstructure and Resistance to Brittle Cracking of TiB2 Coatings Deposited by DCMS

“…Changing the power of the tungsten magnetron affects the plasma density and chamber pressure, which could have resulted in a similar effect as in work [27], i.e., nonstoichiometric Ti-W-B. Smolik et al [19] explained this effect by nanostructures of coatings, which is a consequence of a change in the direction of cracking. By changing the direction of cracking, the energy of a single crack is reduced and can disappear.…”

“…CSM tester was used for nanohardness measurements with a Berkovich diamond indenter with the indenter normal force 350 mN during t = 12 min. Base on Laugier model formula (Equation (2)) [ 19 ], the value of K IC was determined. …”

“…With CNT addition, the Fe-TiB 2 cermet coating shows excellent wear resistance with the lowest volume loss and specific wear rate. J. Smolik et al [17] produced TiB 2 coatings doped with tungsten by magnetron sputtering. In this work, the chemical composition, mechanical properties, and internal structure of the coatings have been investigated.…”

“…In this work, the chemical composition, mechanical properties, and internal structure of the coatings have been investigated. It has been shown that doping TiB 2 coatings with tungsten significantly changes their microstructure and brittle fracture mechanism [17].…”

Properties of Spark Plasma Sintered Compacts and Magnetron Sputtered Coatings Made from Cr, Mo, Re and Zr Alloyed Tungsten Diboride

“…Additionally, until now there has been no information about the use of WB x alloyed by Re, Mo, Cr, Zr as a coatings deposited by magnetron sputtering (MS). However, addition of other transition metals such as tantalum (Ta) [11] or titanium (Ti) [6,17] to α-WB 2 lattice can cause combining of high strength with high fracture toughness in deposited coatings. Deposited films are superhard (H > 40 GPa) and in the case of tantalum can exhibit fracture toughness K 1c values of 3.7 to 3.0 MPa•m 1/2 for increasing Ta content (single-phased up to 26 at.% Ta) [11].…”