Boro-nitriding coating on pure iron by powder-pack boriding and nitriding processes

Abstract

To alleviate spallation and crack difficulties exhibited by a borided metallic surface when it is subjected to a normal, heavy and sliding load under dry conditions, a boron nitride coating was produced on pure iron in two stages: boriding the iron surface at 950 °C for 6 h and then nitriding the pre-borided iron at 550 °C for 6h. The powder-pack technique was used in both stages. XRD measurements confirmed that the grown layers were nitrides and duplex borides. The produced diffusion of the layers reached 240 µm in depth as measured by SEM images. The measured microhardness across the case favoured the interphase cohesion between the iron nitrides and iron borides layers.Consequently, the multicomponent coating exhibited superior wear resistance to an applied normal load under dry sliding contact conditions in comparison to borided iron.

Microstructural and tribological characterization of niobium boride coating produced on AISI 1020 steel via multicomponent boriding

“…Low carbon steels have received attention from as substrates for the application of multicomponent boriding treatments. Boro-chromo-nickelising [24], borocarburizing [25], boro-nitriding [26] and boron-nitro-carburizing [27]. These treatments proved to be efficient in order to improve the ductility and toughness, corrosion resistance, tribological behavior and microhardness comparing to untreated substrates.…”

Boriding and boronitrocarburising effects on hardness,wear and corrosion behavior of AISI 4130 steel

“…These combined treatments improve the lifetime of the machine components by reducing wear, corrosion, surface roughness, and coefficient of friction. To the best of the author's knowledge, very little work has envisaged the combination between these complex surface treatments on steels namely boronitriding [17,18], borocarburising [14][15][16][17][18][19] and borocarbonitriding [20]. In addition, there is a lack of research available that has dealt with combining between surface treatments of nitriding, nitrocarburising and boriding of steels [21,22].…”

Characterization of Different Surface Layers Produced by Solid Boron-Nitro-Carburizing Thermochemical Treatment on AISI 1020

“…Processes limitations and optimizations can be reached by the combination of different thermochemical treatments that can be performed progressively or simultaneously. These treatments are known as Carbonitriding 7,[19][20][21][22] , Nitrocarburizing 10,[23][24][25][26] , Borocarburizing 27,28 or Boronitriding [29][30][31][32][33][34] . A transition zone is formed between the superficial hard layer and the soft substrate -a diffusion zone, were atoms interstitially dissolved in matrix improve fatigue resistance.…”