Corrosion of reduced activation ferritic-martensitic steel - Tungsten brazed joints in liquid lithium

Brazed joints between tungsten and steel are the essential part of the divertor armor block. Meanwhile, liquid Li is considered as a prospective coolant and plasma facing material. Therefore, it is important to estimate the corrosion rate of the brazed seam. Corrosion mechanism in liquid Li at 600 degrees C after 100 h exposure investigated on two types of brazed joints: with Cu and with TiZrBe filler metals. Severe corrosion damage and corrosion failure occur on the brazed seam with Cu filler. Corrosion primarily affects Cu phases in brazed seam. The brazed joint with TiZrBe filler metal shows high corrosion resistance. Results of chemical analysis indicates that corrosion products deposited on specimen surface contain high Fe and Cr content. The corrosion mechanism is similar to corrosion of steel. Corrosion in liquid Li causes preliminary dissolution of Cr-containing phases.