Institute of Fundamental Technological Research

With increasing demand for high-performance and long-lasting cutting and forming tools, the members of this expanding class of superhard metals hold promise to address the shortcomings of traditional tool materials. Those shortcoming include their high cost (silicon nitride, cubic boron nitride, and diamond), their inability to cut ferrous metals due to chemical reactions (diamond), instability in the presence of humidity (cubic boron nitride) and relatively low hardness (tungsten carbide). Also the increasing industrial demand for protective coatings with high hardness, good elastic properties and thermal stability calls for the investigation of new material systems. Although transition metal (TM) nitrides are successfully applied for different tasks in automotive or aero-space industries, the search for improved materials is an ongoing topic, being far from its end. In this work the study on deposition of thin films made of new super-hard materials (SHM) such as tungsten boride are presented. Additionally, the influence of doping by titanium of those materials is investigated. Investigated films were deposited by the pulsed laser deposition method. The used targets were synthetized by SPS method. The powders of boron and tungsten in 4.5 to 1 molar faction were used. The films deposited by PLD method have stoichiometric composition such as used targets. The WB2 and WB3 phase are dominant. Research carried out using SEM, XRD and nanoindentation test showed that the phase composition of the targets is more important in the case of laser deposition than magnetron. All obtained layers are very hard and thermally stable. In the case of magnetron sputtering, smooth layers were obtained while the layers deposited by the laser have a very high roughness. Titanium doping increases the amount of WB3 phase in the sintered discs, while it has no significant effect on the properties of the deposited layers.

laser ablation, tungsten borides doped titanium, plasma sintering