With the aim to determine the potential corrosion effects of solid boric acid (BA) on light water reactors or other BA-involved equipment, the corrosion behaviors of solid BA on 304 stainless steel (SS) at different temperatures were investigated. Upon comparing the corrosion behaviors of solid BA at different temperatures, significant localized corrosion was observed on 304 SS surfaces at 150 °C following 90-day. This localized corrosion exhibited a characteristic pattern of scattered corrosion craters including B-containing Cr-rich oxides. These oxides were found to originate within micro-cracks, gradually evolving into scar-like protrusions within the craters. The proposed corrosion mechanisms entail the interactions between solid BA and chromium oxides/hydroxides, leading to the formation of B-containing Cr-rich oxides. Our findings offer insights into potential corrosion incidents and protective strategies for industries dealing with solid BA.

中文翻译：

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固体硼酸对 304 不锈钢的明显局部腐蚀

为了确定固体硼酸（BA）对轻水反应堆或其他涉及固体硼酸的设备的潜在腐蚀影响，研究了固体硼酸（BA）在不同温度下对304不锈钢（SS）的腐蚀行为。通过比较固体 BA 在不同温度下的腐蚀行为，在 150 °C 下 90 天后，在 304 SS 表面观察到明显的局部腐蚀。这种局部腐蚀表现出包括含硼富铬氧化物的分散腐蚀坑的特征模式。人们发现这些氧化物起源于微裂纹，逐渐演变成陨石坑内的疤痕状突起。所提出的腐蚀机制需要固体 BA 和铬氧化物/氢氧化物之间的相互作用，导致形成含 B 的富铬氧化物。我们的研究结果为处理固体 BA 的行业提供了有关潜在腐蚀事件和保护策略的见解。