Effect of Acid Solutions on Friction and Wear Behaviors of Nuclear Borosilicate Glass

Using an environment-controlled linear reciprocating tribometer, the effect of acid solutions on wear behaviors of nuclear borosilicate glass were studied by rubbing against a stainless stain ball under different pH solutions. Experimental results indicated that the steady-state friction coefficient increased slowly, and the wear damage of the borosilicate glass increased firstly and then decreased when the solution pH increased gradually from 1 to 7. Further analysis showed that the wear mechanism of borosilicate glass in acid solutions strongly depended on the electrostatic effects and contact conditions of the sliding interface. When the pH was less than 2.5, both the borosilicate glass substrate and stainless steel ball were positively charged, the interface repulsive force reduced the direct contact and shear stress of the interface, resulting in the decrease of wear volume of glass materials. When the pH of the solution was 2.5, the borosilicate glass was almost zero-charged, the direct contact between borosilicate glass and stainless steel ball led to the substantial material loss. In contrast, when the pH was higher than 2.5, the borosilicate glass substrate and stainless steel ball were negatively charged and positively charged, respectively. The interface presented the attractive effect, and the hydration layer between the interfaces lubricated the sliding interface, resulting in lower wear volume of both borosilicate glass and stainless steel ball.