Effect of Ni addition and cryogenic hardening on the mechanical and tribological properties of self-lubricating steels produced by MIM

ABSTRACT

This paper addresses the relation between mechanical properties and tribological behaviour of self-lubricating steels produced by in-situ dissociation of SiC. Literature shows that an increase in the mechanical strength of these materials lowers their friction coefficient and wear rates. These works have studied steels with mechanical strength up to 800 MPa, but it is unclear if this trend continues with further increments of mechanical strengths. To tackle this question, self-lubricating steels with Ni and Mo were sintered, half of the samples with 8 wt-% Ni were treated cryogenically hardened. Results show that this trend does not escalate with mechanical strength, furthermore, when ductility is low, graphite reservoirs are not easily accessed, and lubrication is incomplete. Also, plastic deformation allows to better distribute the load of the counter body at the surface, which reduces the wear rates of the specimens and the counter bodies.

KEYWORDS:

• Self-lubricating steels
• cryogenic hardening
• Tribology
• metal injection moulding

Acknowledgements

The authors acknowledge the following Brazilian agencies for funding this research: CNPq, Capes, Embraco S.A., BNDES [grant number 14.2.0220.1] and the Chilean agency Conicyt [grant number 72190023].

Disclosure statement

No potential conflict of interest was reported by the author(s).

Notes on contributors

N. Araya received his Ph.D. in Materials Science and Engineering in 2020 from the Federal University of Santa Catarina, Brazil. Hisresearch activity is focused in the tribological behaviour of sintered materials, self-lubricating composites, durability of solid lubricants and development of wear resistant materials.

L. E. Vieira received his Ph.D. in Materials Science and Engineering in 2014 from the Federal University of Santa Catarina. He is currently an assistant professor at the Regional Blumenau University, Brazil. His main research activity is devoted to metal casting, rheology, powder metallurgy and recycling.

José Daniel B. de Mello is an Emeritus Professor in the College of Mechanical Engineering at the Federal University of Uberlândia, Brazil and visiting professor at the Federal University of Santa Catarina, Florianopolis, Brazil. He received his Doc. Ing. degree in metallurgy from the École Nationale Supérieure d'Electrochimie et Electrométallurgie – Grenoble, France. Professor De Mello's current research are simulation of abrasive wear, sliding and abrasive wear of multi-components ferrous alloys, abrasion-corrosion, surface durability of solid lubricants and tribological behaviour of sintered material.

G. O. Neves received his Ph.D. in Materials Science and Engineering in 2020 from the Federal University of Santa Catarina, Brazil. His main research activity is devoted to synthesis of carbon nanostructures, powder metallurgy, computation thermodynamics and solid lubrication.

C. Binder received his Ph.D. in Materials Science and Engineering in 2009 from Federal University of Santa Catarina, Brazil. He is currently an assistant professor at the Federal University of Santa Catarina, Brazil. His main research activity is devoted to powder metallurgy, plasma processing and surface engineering.

A. N. Klein received his Ph.D. in Engineering in 1983 from Technische Universität Karlsruhe, Germany. He is currently a tenured professor at the Federal University of Santa Catarina, Brazil and has been the coordinator of the Materials Laboratory (Labmat/UFSC) since 1984. His main research activity is devoted to powder metallurgy, plasma processing and surface engineering.

C. Aguilar received his Ph.D in Materials Science and Engineering in 2006 from the University of Santiago, Chile. He is currently a tenured professor at the Federico Santa Maria Technical University, Chile and has been the head of the Research in Powder Metallurgy laboratory (RPM/UTFSM) since 2011. His main research activity is devoted to powder metallurgy, mechanical alloying, and high entropy alloys.

Additional information

Funding

The authors acknowledge the following Brazilian agencies for funding this research: CNPq, Capes, Embraco, BNDES [grant number 14.2.0220.1] and the National Agency for Research and Development (ANID) /Scholarship Program/ Doctorado Becas Chile/ 2018 -72190023.