Borosilicate glasses are widely used to confine high-level radioactive wastes. The lifetime of these materials could reach hundreds of thousands of years if leaching of the glass into groundwater enables the formation of a passivating gel layer. Even in this regime, the glass will never stop corroding as thermodynamic equilibrium between glass and solution cannot be achieved. Therefore, accurate predictions of glass durability including passivation, require a deep understanding of the mechanisms controlling the so-called residual rate. However, despite tremendous efforts, these mechanisms remain poorly understood. Here, focusing on the behavior of the soluble elements of the International Simple Glass (B, Na, and Ca), we show that the residual rate is controlled by the behavior of B, a glass former supposed to dissolve instantaneously when in contact with water and thus widely considered as an ideal tracer. We then demonstrate that B release is controlled by multiple processes highly dependent on the pH. At the beginning of the passivating layer formation, the hydrolysis of B-O-Si linkages is rate-limiting and has an activation energy of ∼60 kJ mol⁻¹, a value slightly lower than that for breaking Si-O-Si linkages. Once the fraction of closed pores resulting from gel restructuring is high enough, then diffusion of both reactants (water molecules) and some products (mainly B_aq, Ca_aq) through the growing gel layer becomes rate-limiting. Consequently, B and Ca accumulate in an inner layer referred to as the active zone, with potential feedback on the B-O-Si hydrolysis. A new paradigm, including B as a key element of the system, is proposed to develop a comprehensive model for the corrosion of borosilicate glass.

硼硅酸盐玻璃被广泛用于限制高放废物。如果将玻璃沥滤到地下水中能够形成钝化凝胶层，则这些材料的寿命可以达到数十万年。即使在这种情况下，玻璃也将永远不会停止腐蚀，因为无法实现玻璃与溶液之间的热力学平衡。因此，要准确预测包括钝化剂在内的玻璃耐久性，就需要对控制所谓残留率的机理有深入的了解。但是，尽管付出了巨大的努力，但对这些机制仍知之甚少。在这里，着眼于国际简单玻璃（B，Na和Ca）的可溶性元素的行为，我们表明残留率受B行为的控制，一种与玻璃接触时能立即溶解的玻璃成型器，因此被广泛认为是理想的示踪剂。然后，我们证明B释放受高度依赖于pH的多个过程控制。在钝化层开始形成时，BO-Si键的水解是限速的，活化能为〜 60千焦耳摩尔^-1，的值略小于用于破碎的Si-O-Si键降低。一旦由凝胶重组产生的闭孔分数足够高，则反应物（水分子）和某些产物（主要是B _aq，Ca _aq）通过生长的凝胶层的扩散就成为速率限制。因此，B和Ca积累在称为活性区的内层中，并具有BO-Si水解的电势反馈。提出了一种新的范式，其中包括B作为系统的关键元素，以开发用于腐蚀硼硅酸盐玻璃的综合模型。