Parameters Affecting Bond Strength and Surface Roughness in Twin Wire Arc Spray Aluminum Coatings

Twin wire arc sprayed coatings are used extensively in the semiconductor/electronics industries.  In certain applications, such as precious metal reclamation, the roughness of arc sprayed aluminum that is obtainable with an arc spray system is desirable. There are many factors that affect the surface roughness in twin wire arc sprayed aluminum.  This study will focus on whether the parameters that enable the applicator to obtain the rough texture desired, have a negative impact on the bond strength of the coating.

Traditional theory of arc spray coatings has been that to obtain a rough coating, the velocity of the particles should be lowered by decreasing the atomizing air pressure of the arc spray system.  Decreasing the air pressure, however, may have a negative impact on the bond strength of the aluminum coating based on traditional thermal spray theory.  It is our belief that this inverse relationship does exist, and that applicators and end users should be aware of the parameters that affect the major properties of twin wire arc sprayed coatings.