Deposition of Tungsten Carbide Thin Films by Simultaneous RF Sputtering

Abstract

Spark-Plasma-Sintering (SPS) of tungsten carbide and titanium carbonitride nanopowders I Zalite, P Angerer, L G Yu et al.-Phase equilibria in the W-C system and tungsten carbides Aleksei S Kurlov and Aleksandr I Gusev-This content was downloaded from IP address 34.208.6.16 Abstract. An interest in WC1-x cubic tungsten carbide results from its catalytic properties similar to those of platinum group metals and the synergistic effect between WC1-x and Pt in reactions of hydrogen evolution and hydrogen oxidation. However, according to the phase diagram of the W-C system, the cubic phase WC1-x only exists in a narrow range of temperature stability (about 2798-3058 K), which makes it difficult for being obtained. To date, there are different methods for synthesizing tungsten carbide powder with a low content of cubic phase that complicates the study of WC1-x properties. A direct plasma dynamic synthesis is known as one of the promising methods to produce WC1-x. The aim of this work is to find the optimal amount of tungsten precursor to obtain cubic tungsten carbide with a high purity by plasma dynamic method. The synthesized products were examined by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The XRD patterns showed that the main phase was cubic tungsten carbide with negligible content of hexagonal tungsten carbide W2C and pure tungsten W. According to a quantitative analysis of synthesized products, which were obtained using masses of initial tungsten equal to 1.0, 0.7, 0.6 and 0.5 gram, the yield of WC1-x phase was 84, 89, 95 and 92 wt%, respectively. The results of TEM displayed that the synthesized powders consist of crystallites, having the size less than 100 nm (WC1-x), and a carbon matrix. This carbon was not detected in XRD due to its presence as an amorphous phase.

Low energy ion-solid interactions: a quantitative experimental verification of binary collision approximation simulations

“…The profile for 20 eV appears close to the surface at position 0.32 nm and width σ = 0.135 nm. The maximum W concentration reaches 24 at% so that we can expect the formation of tungsten carbide, because W atoms come to rest in a carbon environment, the formation enthalpy is slightly exothermic (≈ −40 kJ mol −1 e −1 ), and carbide formation has been observed in similar earlier work [53,54]. For ta-C with higher atomic density the 10 keV W profile shifts towards the surface with position 7.8 nm and width σ = 0.95 nm.…”