锆合金在550℃,25MPa超临界水中的腐蚀行为

Corrosion Behavior of Zirconium Alloys in Supercritical Water at 550 ℃ and 25 MPa

选用了Zr-4,N18(NZ2),N36(NZ8)和M5等4种比较典型的锆合金,在β相水淬及变形后,经过580℃,5h和650℃,2h的热处理,用静态高压釜腐蚀试验研究了锆合金样品在550℃,25MPa超临界水中的耐腐蚀性能。结果表明,4种合金样品的耐腐蚀性能差别明显,Zr-4合金会发生疖状腐蚀,而含Nb的N18(NZ2),N36(NZ8)和M5是均匀腐蚀。获得数量多,分布均匀的纳米尺度的第二相颗粒,对改善锆合金在超临界水中的耐腐蚀性能是有利的,但远不如合金成分的影响巨大。调整合金成分是改善锆合金耐超临界水腐蚀性能的主要途径。

The corrosion behaviors of four zirconium alloys （Zr-4, N18 or NZ2, N36 or NZ8 and MS） have been investigated in the supercritical water （SCW） of 550 ℃ and 25 MPa by autoclave tests. All of the specimens were head-treated at 580 ℃ for 5 h and 650 ℃ for 2 h, respectively, after ,β-quenching and cold rolling. The results showed that the corrosion behaviors of them were distinct. A nodular corrosion appeared on the Zr-4 specimens but uniform corrosions occurred on the others containing Nb alloying element. The nanoscaled second phase particles of uniform distribution and higher density are beneficial to improving the corrosion resistance in SCW. However, the composition of zirconium alloys is a more important factor with a potential possibility for improving the corrosion resistance in SCW by adjusting the composition of zirconium alloys.