Plasma Spray Coating of Aluminum–Silicon-MWCNT Blends on Titanium Grade 5 Alloy Substrate for Enhanced Wear and Corrosion Resistance

In this present research, the wear resistivity of aerospace material titanium grade 5 alloy (Ti6Al4V) is improvised by coating it with 70% aluminium (99% pure) mixed with varying proportions of silicon (30, 25, 20, 15 wt.%) and multiwalled carbon nanotube (MWCNT) (0, 5, 10 and 15 wt.%) by thermal spray method (plasma spray). MWCNT are suitable for higher temperature applications and resist wear and corrosion by acting as a barrier towards the substrate. The powders are mixed well in a ball mill for a period of 24 h and the blended mixture is coated on the substrate. The coating thickness and particle distribution on the substrate is examined through a scanning electron microscope (SEM) and the material is subjected to tensile, microhardness, impact, corrosion and wear tests to determine the improvement on the needed properties as compared with base alloy. Outcomes of the study show that will the inclusion of MWCNT on the substrate enhanced the mechanical, corrosion, and wear properties of the Ti6Al4V alloy due to the higher surface area of MCWNT and better bonding. With the addition of silicon, the eutectic composition formed is a structure of alpha + Si rather than alpha + beta, and thermal fusion forms oxides such as aluminum oxide and silicon oxide. With 15% MWCNTs and Al-Si coating on the surface, a substantial improvement in tensile strength by 29.66%, hardness by 8.24%, impact strength by 41.67%, reduction in wear loss by 25.42% and enhanced corrosion resistance by 63.63% is obtained.