Preparation and properties of CoCrMo-Ni@Al2O3 composite by selective laser melting

Abstract

In this study, nickel coated alumina (Ni@Al 2 O 3 ) particles were prepared via electroless plating, and ball milled with CoCrMo alloy powder in the proportion of 0 wt% to 2 wt%. Then the Ni@Al 2 O 3 reinforced CoCrMo alloy were manufactured by selective laser melting (SLM) process. The microstructure, mechanical property and wear resistance performance of the CoCrMo alloy were characterized. By increasing the content of Ni@Al 2 O 3 particles from 0 wt% to 1.0 wt%, the CoCrMo alloy kept flawless with the highest hardness of 435 HV 1 and best abrasion performance, which could be attributed to the pinning dislocation slip effect of Al 2 O 3 phase and the metallurgical bonding of Ni phase with CoCrMo alloy during the SLM process. When the content of Ni@Al 2 O 3 increased to 2 wt%, the inconsistent fluidity between Ni@Al 2 O 3 and CoCrMo powders has led to the uneven distribution of mixed particles during the powder spreading process, which resulted in the lowest compressive strength and wear resistance. • In the field of joint replacement surgery, the SLM-processed CoCrMo alloy implants are gaining more popularity for their excellent mechanical properties. In order to promote the wear resistance and prolong the service life of implants, small amounts of ceramic particles can be added into the alloy matrix. • In this work, we have fabricated the uniformly core-shell structure of Ni coated Al 2 O 3 particle by electroless plating, and the CoCrMo composites with different amounts of Ni@Al 2 O 3 particles were prepared by SLM technology. As the Ni phase acted as a bridge during the melting process, the surface of CoCrMo-Ni@Al 2 O 3 composites were smooth without obvious cracks. Moreover, the CoCrMo composites demonstrated better wear resistance and stable coefficient of friction for the introduction of Al 2 O 3 .