Factors affecting bonding of metals

Abstract Adhesives have several advantages over mechanical fastening, and the use of bonding is steadily increasing in many applications. Bonding of primary structures in aircraft has been used for many years and much more research has been directed towards aluminium than any other material. Joint performance depends on the alloy, pretreatment, primer, and adhesive. Many studies of these variables have been made, often making use of modern surface analytical techniques. Informative studies have also been carried out on titanium and steel. Hot, humid conditions, especially combined with stress, can be especially damaging to metal joints. A full understanding of the factors that provide the best resistance to this damaging effect has not yet been achieved. However, stable oxide layers with the correct topography appear critical and selection of the correct pretreatment is therefore of paramount importance.MST/475