The Role of Water in Oxide Polishing

Other workers as This section first describes how water 

Cook suggests that water entry under the load imposed by the indenter is similar to water entry under the load imposed by the abrasive particle. As the abrasive particle moves across the surface, a strain field develops in the glass surface due to the load and velocity of the particle, with compressive strain in front of the particle and tensile strain behind the particle. In front of the particle, hydrostatic pressure leads to water entry into the oxide as the abrasive pushes water into the surface. However, diffusion of water into the oxide is inhibited by the compressive strain occurring in front of the particle. The diffusion coefficient of water decreases exponentially with compressive strain and increases exponentially with tensile strain. The difference between the traveling indenter (i.e., the abrasive particle) and the static indenter (i.e., the Knoop indenter) is the tensile strain that occurs in back of the traveling indenter leads to accelerated diffusion of water into the oxide. Thus, one of the functions of the abrasive particle is to pump water into the oxide surface. Water enters the oxide under the influence of the hydrostatic pressure in front of the particle and diffuses further into die oxide in back of the particle. The depth to which water diffuses into the oxide is a function of abrasive particle 

Infrared (IR) orbance spectra at various locations of a Knoop indentation mark made in air. (From Ref. (4).) 

Water entry into the oxide surface weakens the glass network by breaking Si-0 bonds. As a consequence, the hardness of the glass surface is reduced by water entry. The general reaction for the interaction of Si-0 and HjO is  

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