Tribocorrosion behavior of graphene-based solid lubricants biofunctionalized with hyaluronic acid on CoCr surfaces

In this work graphene-based solid lubricants biofunctionalized with hyaluronic acid were deposited on CoCr surfaces to decrease wear-corrosion phenomena. Graphene oxide was electrochemically reduced on CoCr in an aqueous suspension of graphene oxide 4 g/L by cyclic voltammetry. Biofunctionalization in phosphate buffer solution with HA 3 g/L (PBS-HA) for 24 h was performed. A pin-on-disk tribometer with an integrated cell was used for tribocorrosion tests. Wear-corrosion tests were performed against AISI316 steel balls applying normal load 1 N, 120 rpm for 500 m, in PBS and PBS-HA. Coefficients of friction in PBS were higher than in PBS-HA. ErGO and HA-ErGO increased wear rate in AISI316 balls, i.e., ErGO hardens the CoCr surface. Bio- functionalization reduces abrasive properties of ErGO deposits.