Microscratching and fretting of electro-co-deposited Cr-based composite coatings with BN, graphene, and diamond reinforcements

Herein, enhanced damage tolerance of electrochemically processed Cr-based coatings reinforced with BN (Cr-BN), diamond (Cr-D) and graphene (Cr-Gr) is presented. The effect of micro-meter sized BN and diamond particles as well as 2D graphene nano-flakes in Cr matrix is studied due to its excellent mechanical properties and lubricating nature. The highest hardness of Cr-D (similar to 23 GPa) is ascribed to the highest dislocation density of similar to 18x10(11) cm(-2), estimated through Taylor's model. Scratch test revealed minimum wear volume and coefficient of friction of similar to 27 +/- 0.47 x 10(-14) m(3) and 0.14, respectively, for Cr-D coating. Fretting wear results were concurrent with the scratch test, with Cr-D exhibiting minimum coefficient of friction (COF similar to 0.53) and wear loss (wear volume similar to 0.222 x 10(-3) mm(3)). Diamond particles promote strong bonding due to mechanical interlocking, and efficient load transfer that restricts wear, and passes as a suitable reinforcement of Cr-coating for tribological applications subjected to high load and temperature conditions. [GRAPHICS] .

Automated summary

The research investigates the effect of BN, diamond, and graphene particles in Cr-based coatings, with diamond particles showing the highest dislocation density and hardness, resulting in reduced wear and friction. Diamond particles are found to promote strong bonding and efficient load transfer in the coating, making them a suitable reinforcement for tribological applications under high load and temperature conditions.