Tribology–Structure Relationships in Silicon Oxycarbide Thin Films

Abstract

Silicon oxycarbide is a versatile material system that is attractive for many applications because of its ability to tune properties such as chemical compatibility, refractive index, electrical conductivity, and optical band gap through changes in composition. One particularly intriguing application lies in the production of biocompatible coatings with good mechanical properties. In this paper, we report on the wide range of mechanical and tribological property values exhibited by silicon oxycarbide thin films deposited by reactive radio frequency magnetron sputtering. Through a change in oxygen partial pressure in the sputtering plasma, the composition of the films was controlled to produce relatively pure SiO2, carbon-doped SiC, and compositions between these limits. Hardness values were 8–20 GPa over this range and the elastic modulus was measured to be between 60 and 220 GPa. We call attention to the fit of the mechanical data to a simple additive bond-mixture model for property prediction. Tribological parameters were measured using a ball-on-disk apparatus and the samples exhibited the same general trends for friction coefficient and wear rate. One film is shown to produce variable low friction behavior and low wear rate, which suggests a solid-state self-lubrication process because of heterogeneity on the nanometer scale

Modeling of amorphous SiCxO6/5 by classical molecular dynamics and first principles calculations

“…As shown in Fig. 6 , the Young’s modulus of SiCO increase with an increased carbon content, as reported by nanoindentation test 29 . Within different compositions, it ranges from 99 GPa to 120 GPa, which is within the scope of 90–110 GPa in experiments 5 30 .…”

An Investigation of the Nanomechanical Properties of 0.5Ba(Ti0.8Zr0.2)O3–0.5(Ba0.7Ca0.3)TiO3 Thin Films

“…(a), its friction force is the lowest. Tribological interactions are known to be extremely complex, depending on roughness, tribochemical reactions, and structural rearrangement, all of which have great effects on the tribological properties . In this experiment, all of the samples were measured under constant surrounding temperature and humidity, using a certain AFM tip; therefore, no structural rearrangement was expected to occur, and the tribochemical reactions were supposed to be similar for all the films, as the amounts of atoms which compose the films are very much the same.…”

Additive manufacturing of ceramics from preceramic polymers: A versatile stereolithographic approach assisted by thiol-ene click chemistry

“…9 C and D. Over a range of penetration depths, the mean values of the reduced Young's modulus and hardness are found to be 106±6 and 12±1 GPa, respectively. An earlier study showed that SiOC ceramics with lower O/C ratios behave similarly to amorphous-SiC materials, while the mechanical properties of SiOC with higher O/C ratio are similar to those in amorphous SiO2 [37]. In the present work, the hardness and elastic modulus of AM fabricated SiOC materials lie between the predicted limit of amorphous SiO2 [37] and amorphous SiC [38] and are further in good agreement with reported values for silicon oxycarbide glasses with variable C/O ratio [37,39].…”

“…An earlier study showed that SiOC ceramics with lower O/C ratios behave similarly to amorphous-SiC materials, while the mechanical properties of SiOC with higher O/C ratio are similar to those in amorphous SiO2 [37]. In the present work, the hardness and elastic modulus of AM fabricated SiOC materials lie between the predicted limit of amorphous SiO2 [37] and amorphous SiC [38] and are further in good agreement with reported values for silicon oxycarbide glasses with variable C/O ratio [37,39]. It is worth emphasizing that our fabrication method resulted in SiOC ceramics with comparable or even slightly better mechanical properties than those of SiOC glasses fabricated either via hot-pressing or via radio frequency (RF)-magnetron sputtering.…”