Fe-Me-B Diffusion Layers for Surface Modification of Carbon Steels

Abstract:

Multicomponent boron-based diffusion layers are capable to provide a wider variety of surface improvements compared to pure boriding. In this research, we consider a way to increase mechanical properties of carbon steels by using two-component thermal-chemical treatment (TCT) such as boroaluminizing (B+Al), and boronickelizing (B+Ni). Diffusion treatment of steel surface was carried out by pack method in powder mixtures, and pastes, containing the above-mentioned elements and sodium fluoride as an activator. The exposure time was 3 hours, the treatment temperature was 950 °C. Pure boriding was conducted additionally to compare with two-component methods. The metallographic analysis revealed diffusion layers with a tooth-like structure after boriding and B+Ni. Typical composition of boride layer with iron boride FeB as an outer phase and Fe₂B as an inner one was obtained after the first method. EDS analysis revealed a small amount of Ni (less than 1%) in boronickelized layer. Although XRD analysis revealed Ni₂B, Fe₃Ni₃B besides iron borides and carboborides after B+Ni. Another structure was obtained after B+Al – namely a layered microstructure with outer softer iron aluminides and iron borides beneath. The thickest layer was obtained after boriding with the thickness of 140-160 μm, where higher value corresponds to low-carbon steel and vice versa. While for boroaluminizing the layer thickness was around 120-140 μm and for boronickelizing - 60-100 μm. Microhardness profiles differ significantly depending on the TCT method. For instance, initial high values followed by a drastic drop of hardness for boriding and boronickelizing. Wave type profiles characterize the microhardness distribution on boroaluminized samples. Wear tests indicated that samples with boride layer were the most wear resistant and the least resistant were the samples after B+Al. Fe-Me-B layers with the tooth-like structure are superior to the ones with the layered structure.

• Periodical: Defect and Diffusion Forum (Volume 403)
• Pages: 47-56
• DOI: https://doi.org/10.4028/www.scientific.net/DDF.403.47
• Online since: September 2020
• Authors: Undrakh Mishigdorzhiyn*, Zhambal Samaev, Vladimir Mosorov, Nikolay Ulakhanov
• Keywords: Boroaluminizing, Boronickelizing, Metallography, Microhardness, Multicomponent Diffusion Treatment, Thermal-Chemical Treatment, Wear Resistance

References

[1] L.G. Voroshnin, O.L. Mendeleeva, V.A. Smetkin, Teoriya i tekgnologiya khimiko-termicheskoi obrabotki [Theory and Technology of Thermal-Chemical Treatment], Novoe Znanie, Moscow, (2010).

[2] F. Xie, S. Xu, J. Pan., Novel Pack Cementations: Alternating Current Field Enhanced Pack Cementations, Mater. Perform. Charact. 7, Issue 5 (2018) 1164-1177.

DOI: 10.1520/mpc20180008

[3] M.G. Krukovich, B.A. Prusakov, I.G. Sizov, Plastichnost borirovannykh sloyov [Plasticity of boronized layers], Fizmatlit, Moscow, (2010).

[4] S.V. Grachev, L.A. Mal'tseva, T.V. Mal'tseva, A.S. Kolpakovf, M.Yu. Dmitriev, Boronizing and borochromizing in a vibrofluidz bed, Met. Sci. Heat Treat. 41 (1999) 465–468.

DOI: 10.1007/bf02471210

[5] Yu.A. Balandin, Termochemical treatment in fluidized bed. Surface hardening of die steel by diffusion boronizing, borocopperizing and borochromizing in fluidized bed, Met. Sci. Heat Treat. 47, (2005) 103–106.

DOI: 10.1007/s11041-005-0037-z

[6] S. Sen, U. Sen, The effect of boronizing and borochromizing on tribological performance of AISI 52100 bearing steels, Ind. Lubr. Tribol. 61 (2009) 146–153.

DOI: 10.1108/00368790910953668

[7] V.I. Mosorov, A.M. Guryev, B.D. Lygdenov, D.S. Filchakov, Uprochnenie poverkhnosti litoi stali kompleksnym diffuzionnym nasyscheniem borom i khromom [The hardedning of surfaces of steel by complex diffusion saturation with boron and chrome], In Obrabotka metallov. 2 (2011) 33-36.

[8] I.G. Sizov, U.L. Mishigdorzhiyn, D.M. Maharov, A study of thermocycling boroaluminizing of carbon steel, Met. Sci. Heat Treat. 53 (2012) 592–597.

DOI: 10.1007/s11041-012-9440-4

[9] U. Mishigdorzhiyn, I. Sizov, The influence of boroaluminizing temperature on microstructure and wear resistance in low-carbon steels, Mater. Perform. Charact. 7 (2018) 252–265.

DOI: 10.1520/mpc20170074

[10] A. Bartkowska, A. Pertek, The influence of nickel coating on diffusion boriding of C45 constructional steel, Surf. Eng. 2 (2009) 89–92.

[11] A. Bartkowska, A. Pertek, M. Popławski, D. Bartkowski, D. Przestacki, A. Miklaszewski, Effect of laser modification of B–Ni complex layer on wear resistance and microhardness, Optics & Laser Technology. 72 (2015) 116–124.

DOI: 10.1016/j.optlastec.2015.03.024