An XPS study of the adherence of refractory carbide silicide and boride rf-sputtered wear-resistant coatings

Abstract

Radio frequency sputtering was used to deposit refractory carbide, silicide, and boride coatings on 440-C steel substrates. Both sputter etched and pre-oxidized substrates were used and the films were deposited with and without a substrate bias. The composition of the coatings was determined as a function of depth by x-ray photoelectron spectroscopy combined with argon ion etching. Friction and wear tests were conducted to evaluate coating adherence. In the interfacial region there was evidence that bias may produce a graded interface for some compounds. Biasing, while generally improving bulk film stoichiometry, can adversely affect adherence by removing interfacial oxide layers. in all cases but the iron oxide coverage was only complete on the preoxidized substrates. The film and iron oxides were mixed in the MoSi2 and Mo2C films but layered in the Mo2B5 films. In the case of mixed oxides, pre-oxidation enhanced film adherence. In the layered case it did not.

Pressureless reactive sintering of ZrB2 ceramic

“…The binding energy for both types of B-based oxides are in agreement with literature values. [25][26][27][28] These results would suggests the presence of B oxides, which are known to reduce the densification and favor grain coarsening, explaining the results from the microstructure analysis. The presence of a non-stochiometric B 2 O x can be related to the evaporation of rapidly evolving gas species, such as BO, from B 2 O 3(l) at these temperatures This gas evolution was observed during sintering of B 4 C by Dole et al 29 Chamberlain et al 14 reported that the presence of WC impurities from milling played a vital role in the removal of the surface oxide film.…”

Enhanced diffusion upon amorphous-to-nanocrystalline phase transition in Mo/B4C/Si layered systems

“…Compared to conventional x-ray photoelectron spectroscopy ͑XPS͒, HAXPES takes advantage of a higher x-ray energy, which increases the inelastic mean free path of the photoelectrons from typically 2.5 nm ͑XPS at 1486.6 eV͒ to 3.5 nm-6 nm ͑HAXPES at 2010 eV and 4020 eV, respec-tively͒. Additionally, clear shifts in the Mo 3d 5/2 ͑Ϫ0.26 eV, in accordance with a MoSi 2 -induced shift 19 ͒ and Si 2s peaks ͑+0.35 eV͒ indicate compound formation. The HAXPES measurements have been performed at the "HIKE" experimental station 16 times at 500°C, were first characterized with LEIS and subsequently investigated with HAXPES.…”

Evolution of structure and mechanical properties of hard yet fracture resistant W‐B‐C coatings with varying C/W ratio

“…The peak deconvolution for the B1s high resolution spectra showed four peaks. The peaks were observed at the binding energies of 187.5 eV, 187.9 eV, 189.3 eV and 191.9 eV and were assigned to B-B[22], B-W[23], B-C[24] and B-O[25] bonds, respectively. The C1s high resolution spectra are shown inFig.1(c).…”