Investigation on Microstructure, Hardness, and Corrosion Resistance of Mo–Ni–B Coatings Prepared by Laser Cladding Technique

Abstract

The hard and corrosion resistant coatings of Mo 2 NiB 2 cermet were prepared by the laser cladding technique. The influences of the Mo:B ratio and the laser scanning speed on the microstructure and property of the Mo 2 NiB 2 cermet coatings were investigated. The results showed that the laser scanning speed of 1.5 mm/s and the Mo:B ratio of 1 were more beneficial to the formation of Mo 2 NiB 2 cermet than 2.0 mm/s and 0.8, 1.2, respectively. The amount of the Mo 2 NiB 2 ceramic phases were decreased from the top layer to the bottom layer of the coating. The changes of microstructure and composition led to the changes of hardness and corrosion resistance of the Mo 2 NiB 2 cermet coatings. The coating prepared at the Mo:B ratio of 1 and the scanning speed of 1.5 mm/s possessed the highest hardness, and the hardness gradually decreased from the top layer to the bottom layer of the coating. The formation of Mo 2 NiB 2 and {FeM} phases led to the enhanced corrosion resistance of the Mo 2 NiB 2 cermet coatings, and the coating prepared at the Mo:B ratio of 0.8 possessed the best corrosion resistance and the minimum corrosion current.al. [1,10,12] also prepared Mo 2 NiB 2 cermet by reaction boronizing sintering and found that the TRS and hardness of the Mo 2 NiB 2 cermet were 2.35 GPa and 84.5 HRA, respectively. Plus, the addition of Cr and V elements further enhanced the TRS, hardness, and corrosion resistance of the Mo 2 NiB 2 cermet. Besides the reaction sintering method, other methods like high-velocity oxy-fuel (HVOF), plasma spraying, detonation gun spraying and laser cladding, etc., can also provide high energy for the reactive synthesis of Mo 2 NiB 2 cermet coatings [15][16][17][18][19]. Nonetheless, each method has its own characteristics, which induces the significantly different effects of the methods on the Mo 2 NiB 2 cermet coatings. Among these synthesis methods, the laser cladding technique possesses superior properties like environmental friendship, good artificial controllability, high efficiency and energy, and convenience [20]. Thus, the laser cladding technique is the desirable and excellent method to fabricate the Mo 2 NiB 2 cermet coatings, which has been applied in the preparation of the Mo 2 NiB 2 cermet coatings. Hu et al. [14] prepared the Mo 2 NiB 2 (M 3 B 2 ) cermet coatings by laser cladding and found that the pretreatment and re-melting afterwards could greatly affect the microstructure and properties of the coatings. Wu et al. [13] found that laser cladding fabricated Mo 2 NiB 2 cermet coatings possessed high hardness, good wear and corrosion resistance. However, these works mainly focused on the preparation and property characterization of Mo 2 NiB 2 cermet coatings, and how the laser cladding parameters influenced the property were not deeply discussed. Therefore, the comprehensive investigations on the influences of the laser cladding process on the microstructure and property of Mo 2 NiB 2 cermet coatings are quite needed, which is beneficial for widening the application of Mo 2 NiB 2...

Investigation of the Tribological Behavior and Microstructure of Plasma-Cladded Fe–Cr–Mo–Ni–B Coating

“…Binary boride easily reacts metallurgically with the other alloying elements, which is the common method for the synthesis of ternary borides. Mo–Fe–B and Mo–Ni–B are ternary boride systems that have been widely studied in recent years [ 9 , 10 ]. Zhang et al [ 11 ] reported that ternary boride-based cermets exhibited excellent mechanical properties with fine-grained Mo 2 FeB 2 cermets, which were prepared by the two-step sintering technique.…”

Evaluation of Corrosion Resistance of Thin Films Formed on AISI 316L Steel by Plasma Using Hastelloy as Cathodic Cage

“…In the past decades, the deposition of thin films has been a strategic alternative to provide improved surface properties. The development of protective layers on metallic substrates has enabled good wear resistance, [1][2][3][4][5][6][7][8][9][10] corrosion protection, [11][12][13][14][15][16][17][18][19][20][21][22][23][24] enhanced surface hardness, [25][26][27][28][29][30][31][32][33][34] and superior biocompatibility. [18,20,[35][36][37][38][39][40] Plasma deposition procedure is a promising technique that can be used to supply thin films, aiming at applications such as magnetron sputtering, [2,3,6,10,12,18,…”

“…In the past decades, the deposition of thin films has been a strategic alternative to provide improved surface properties. The development of protective layers on metallic substrates has enabled good wear resistance, [ 1–10 ] corrosion protection, [ 11–24 ] enhanced surface hardness, [ 25–34 ] and superior biocompatibility. [ 18,20,35–40 ]…”

Mechanical Investigations of ASTM A36 Welded Steels with Stainless Steel Cladding

“…In general, these coated surfaces provide wear resistance characteristics [36][37][38][39][40][41][42][43]. They are also commonly exposed to the systems having both mechanical and corrosion wear phenomena [44][45][46][47][48]. Most importantly, they must operate at elevated temperatures for a long time without thermal fatigue [49] and creep [50] failures.…”