Effects of water immersion and humid weathering on the near‐surface mechanical properties of phosphate laser glass

Abstract

In this paper, the effect of water immersion and humid weathering on the nearsurface mechanical properties of phosphate laser (PL) glass was investigated using nanoindentation. The results indicate that, in the water immersion condition, the reduced modulus and nano-hardness of PL glass decrease first, then increase and finally keeps unchanged with the increase in immersion duration; however, in the humid weathering condition, they decrease monotonously. The reaction mechanism occurring between water molecules and the glass network, especially during the later stage of the reaction process, determines the near-surface mechanical properties and their differences when exposed to water and/or humid air. The results in this paper provide additional insight into the nano-mechanics of glass surfaces, which also help understand the surface alteration process of phosphate laser glass during machining, storage, and serving in wet environments.

Beyond surface nanoindentation: Combining static and dynamic nanoindentation to assess intrinsic mechanical properties of chemical vapor deposition amorphous silicon oxide (SiOx) and silicon oxycarbide (SiOxCy) thin films

“…Only three models (the Bec [19], Song-Pharr [24,31] and Korsunsky [21,33] models) provide consistent values of Ef or Hf (i.e. close to the one found for the corresponding thick films and in good agreement with literature for similar silica glass [25,26,28]) as shown in Figure 3a and b for TEOS samples, Figure 4a and b for HMDS samples.…”

“…Such a superficial 10 nm-thick layer containing 4 at.% of carbon has been previously observed for 120 nm-thick-TEOS-like samples [12]. Due to higher hydration and to the presence of organic moieties [25][26][27][28], this superficial layer is expected to present lower Young modulus and hardness. Nevertheless, it could be overlooked due to its thinness compared to the values of t (from 63 to nm, as shown in Table 1) and because, as previously mentioned, only the data obtained for h  50 nm are considered.…”

“…The presence of hydrated and organic moieties is known to generally decrease the value of E and H for silicon oxide materials. Classically, silicon oxides have E and H ranging, respectively, from 73 to 20 GPa and from 8 to 5 GPa depending on the level of hydration [25,26,28]. Silicon-oxide-based materials containing organic moieties can be found with E between 20 and 3 GPa and H between 3 and 0.2 GPa depending on the content of organic carbon [11,27,29].…”

“…However, it neglects the presence of surface modifications formed by hydration or contamination due to atmospheric exposure [25]. Such a superficial 10 nm-thick layer containing 4 at.% of carbon has been previously observed for 120 nm-thick-TEOS-like samples [12].…”