Composite electroplating - Settings and applications

In today's tense economic climate, surface protection increasingly requires parts to withstand stresses involving several phenomena simultaneously (friction, abrasion, corrosion, impact, etc.). The trend is therefore either to use solutions involving several surface treatment technologies, or to resort to composite deposits (or alloys).

Composite surface treatments lead to multifunctional coatings, enabling the combination of sometimes antagonistic surface properties. What's more, they enable the client to work with a single subcontractor, thus reducing lead times. Because of these advantages, considerable research is underway worldwide in all sectors of industry.

Among the most common functions fulfilled by surface treatments are anti-wear and anti-corrosion. But today's processes are becoming multifunctional in order to simultaneously provide these properties as well as seizure resistance, thermal protection, tribological and tactile properties, etc.

Surface treatments are expected to perform the following functions:

• reduced contact pressures ;

• improved lubrication ;

• lower coefficient of friction ;

• adhesion wear resistance ;

• homogenization of surface layers ;

• valuing residual compressive stresses ;

• increased surface hardness for abrasion-erosion wear resistance ;

• resistance to oxidation ;

• particle trapping due to roughness ;

• noise and vibration control ;

• thermal protection ;

• electrical and/or electromagnetic properties.

After having discussed the modeling of phenomena involved in electrolytic codeposition in the article Composite electrodeposits - Modeling , we will focus on the parameters involved in these processes and the industrial applications of these coatings.