Epoxy\Epoxy Composite\Epoxy Hybrid Composite Coatings for Tribological Applications-A Review

Abstract

Epoxy composite coating systems generally find their usage in applications such as, fluid handling systems to protect components from corrosive media. However, their use in demanding tribological applications such as, in sliding components of machines, are known to be limited. This is often attributed to their low load bearing capacity combined with poor thermal stability under severe p-v regimes. Researchers have tried to enhance the tribological properties of the epoxy coatings using a combination of several types of micro/nano sized fillers to produce composite or hybrid composite coatings. Hence, this review paper aims to focus on the recent advances made in developing the epoxy coating systems. Special attention would be paid to the types and properties of nano-fillers that have been commonly used to develop these coatings, different dispersion techniques adopted and the effects that each of these fillers (and their combinations) have on the tribological properties of these coatings.

Keywords: epoxy coatings; friction; tribology; wear.

Figure 1

Classification of different types of coatings.

Figure 2

Classification of different fillers used to reinforce epoxy matrix.

Figure 3

Optical microscopy (a,d,g) and scanning electronic microscopy(b,c,e,f,h,i) of scratches showing cracks for epoxy coating without filler (P), and nanocomposite coatings with Al₂O₃ (A) and ZnO (Z) Fillers [81].

Figure 4

Comparison of effectiveness of LBE non-hybrid coatings in reducing (a) friction coefficient, (b) wear rate, under dry sliding conditions.

Figure 5

(a) FESEM image of unworn surface (b) AFM image of same surface showing bumpy texture [26].

Figure 6

Comparison of effectiveness of LBE hybrid composite coatings in reducing (a) friction coefficient, (b) wear rate, under dry sliding conditions.

Figure 7

Scratch Map, reproduced from [88].