Boride Layer of Austenitic Spheroidal Graphite Cast Iron Boronized in Fluidized Bed Its Corrosion and Wear Resistance

Abstract

  Boronizing in the fluidized bed was performed on the surface treatment of austenitic spheroidal graphite cast iron. Tests were carried out on the hardness, microscopy. X-ray diffractometry, electron microprobe X-ray analysis, glow discharge spectrometry, friction and wear characteristic, and the corrosion behaviors in boronized specimens. As a result, the boride layer in the austenitic spheroidal graphite cast iron produced by fluidized bed was 1400 HK in hardness and consisted of two intermetaltic compounds (FeB, Fe₂B), The enrichment of Si and Ni excluded from the horonized compound was detected like the stripe. The boride layer more improved friction properties and the wear resistance of austenitic spheroidal graphite cast iron than those of SUS304 and Al₂O₃. The corrosion resistance against 0.1 N HCl and 0.1 N H₂SO₄ of the boronized specimen was more improved compared to untreated specimens. It was found that the boronizing method in fluidized bed could be successfully applied to the surface treatment of austenitic spheroidal graphite cast iron.