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Chlorine induced high-temperature corrosion mechanisms in HVOF and HVAF sprayed Cr3C2-based hardmetal coatings

Research output: Contribution to journalArticleScientificpeer-review

Details

Original languageEnglish
Article number108166
JournalCorrosion Science
DOIs
Publication statusE-pub ahead of print - 14 Aug 2019
Publication typeA1 Journal article-refereed

Abstract

A novel method that combines thermal analysis and traditional furnace corrosion tests was used to study the corrosion behaviour of thermally sprayed Cr3C2-based hardmetal coatings at 450 °C and 550 °C under a KCl deposit. This method enabled the identification of the onset temperature of chlorine-induced oxidation to be within 450–500 °C. Two corrosion mechanisms were suggested for these temperatures. At 450 °C, the corrosion rate was slow and mainly controlled by the formation of K2CrO4. Exposure at 550 °C caused the formation of fine interconnected secondary-carbide precipitates in the metal matrix. Their fast corrosion was identified as the major cause of degradation.

Keywords

  • A. Metal matrix composites, A. Superalloys, B. SEM, B. TGA, B. XRD, C. Chlorination, C. High temperature corrosion, C. Thermodynamic diagrams

Publication forum classification

Field of science, Statistics Finland