Formation of Tribotechnical Al-Cu Coatings with Functional Additives by Centrifugal Induction Surfacing

Abstract

The article presents the results of metallographic and tribotechnical studies of composite coatings based on aluminum with a high copper content formed on the inner surface of the workpiece by centrifugal induction surfacing. According to the results of the study, with a copper content of more than 40 wt.% a composite structure is formed based on the θ-phase (Al2Cu) with inclusions of т-phase grains (Cu3NiAl6 ), particles of silicon, tin and iron-containing phases. This structure has a high hardness and a parameter of the coefficient of thermal linear expansion close to steel, so that the coating does not peel off from the steel base. It is also shown that tin introduced into the melt does not form intermetallide compounds and is released in its pure form, acting as a solid lubricant and reducing the coefficient of friction to 0.03 at loads up to 20 MPa.

Keywords

• al-cu alloy
• silicon
• tin
• induction surfacing
• sleeve
• metallographic analysis
• hardness
• coefficient of friction