Formation of a corrosion-resistant layer on steel by reaction with a Si sub 3 N sub 4 - Al sub 2 O sub 3 composite under the conditions of light-thermal treatment

The formation of a surface layer on low-alloyed steel during light-thermal treatment with a composite material based on Si sub 3 N sub 4 -Al sub 2 O sub 3 was investigated. The working surfaces were studied using metallographic, x-ray diffraction, and electron-probe microanalysis. It was found that the corrosion-resistant phases Al sub 2 SiO sub 5 , (Fe,Cr) sub 2 O sub 3 , (Cr,Al) sub 2 O sub 3 , and NiCrO sub 4 formed in the alloyed layer, increasing its microhardness by 2-5 times and its corrosion resistance in sea water by more than two orders of magnitude.