Water Stress Corrosion in a Directly Bonded Borofloat Glass Interface

In this article, the phenomenon of water stress corrosion (WSC) at borofloat glass interfaces joined by hydrophilic direct bonding is explored. In particular, the impact of the surface waviness and surrounding atmosphere is studied through time-resolved measurements of the bonding energy during surface separation. We present a model for sub-critical crack growth and discuss the underlying WSC reaction. Key findings are that, firstly, the presence of humid air, and secondly, mechanical stress stored at the interface due to elastic contact point deformation increase the number of water molecules with sufficient kinetic energy to participate in the WSC reaction, that is, increase the reaction rate. This study provides crucial insights into the conditions aggravating WSC and gives implications for improving the durability and performance of mechanically stressed glass interfaces in various applications, such as micro-electro-mechanical systems (MEMS) and advanced optics.