Fine grained titanium carbonitride reinforcements for laser deposition processes of 316L boost tribocorrosion resistance in marine environments

Abstract

316L stainless steel has recently gained relevance as metal for additive manufacturing thanks to its high versatility in many laser deposition processes combined with its excellent mechanical and corrosion properties. However, its use in oil & gas, marine or biomedical applications is limited by its poor tribocorrosion performance, since it is prone to wear-accelerated corrosion. On the quest for extending the applicability of 316L components deposited by laser processes to tribocorrosion applications, the present work develops 316L laser claddings reinforced with titanium carbonitride grains. An agglomerated and sintered (Ti,Mo)(C,N)-Ni powder was designed for preserving the chemical integrity of the hard phases during the laser deposition process. This results in 316L composites with homogeneously distributed titanium carbonitride reinforcements with a size ranging from sub-micrometre up to about 2 µm. These 316L composites improve the tribocorrosion performance in artificial seawater by over 10 fold in open circuit potential conditions and over 30 fold at an applied passive potential. The passivity of the 316L composites is maintained even though of a lower break down potential. These results highlight the enormous potential of 316L reinforced with titanium carbonitride deposited by laser processes for wear resistant components operating in saline environments.

Keywords

• 316L stainless steel
• Titanium carbide, titanium carbonitride
• Laser cladding
• Tribocorrosion
• NaCl