from the conferences organized by TANGER Ltd.
The abstract is describing results of characteristics studies of ceramic coatings made from corundum-baddeleyite ceramics, on deposit, boronized corrosion-proof steel AISI 303. Boronizing of steel surface is a technology known for tenths of years. In addition to higher surface strength leading to abrasion resistance some versions of boronisation may contribute also to corrosion-proof protection of the steel. Benefits of these applications can be multiplied by formation of ceramic coatings with higher strength, fire resistance and lower surface porosity. Borides in such a case form on the steel interlayers with suitable coefficient of linear thermal expansion to ceramic coatings which are applied by the method of thermal spraying or plasma spraying. Conditions of boronizing by the method of reactive fusion of boron from boron carbide and lanthanum hexaboride are described so the formation of Fe2B is preferred to FeB, which is more fragile and the structure of which does not comply with conditions for perfect adhesion of modified zirconium ceramics. Perfect adhesion connection of needle-like anchored interlayers of Fe2B in corrosion-proof steel AISI 303 prepared by reactive diffusion of boronizing media without activating agents under temperature 1000 °C and with exposure 2 – 4 hours is proving during pin-off tests values of the bond strength 20 MPa – 25 MPa. Ceramic coatings made from Eucor Al2O3-ZrO2 formed on these interlayers have bond strength value 9 MPa – 13 MPa. Thermic cycling in the interval 100°C – 600 °C confirmed good bond strength of coatings with the base steel. The static cycling under higher temperatures (600-1000 °C) proved already higher number of failures of bond strength and mechanical destructions of coatings.
Keywords: boronised steel, plasma spraying, ceramic coatings, bond strength; zirconia coatings© This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.