OPTIMA - Optimisation of a chrome-free pre-treatment process for lightweight alloy components

The increasing use of Al by vehicle OEMs is driven by its high strength to weight ratio, enabling substantially

improved fuel economy & reduced CO2 emissions when substituted for heavier materials. However, the change

of material presents new challenges with respect to design & methods of joining. The pre-treatment of the Al

surface prior to bonding is the key to long service life. Pre-treatments successfully employed by the aerospace

industry cannot be used in automotive production, where cheaper & more environmentally friendly pre-

treatments are required. Specifically, the use of chromates is unacceptable. Hence, there is a need to develop

chromate-free pre-treatments that will consistently provide the required level of performance, whilst being

acceptable both in terms of general engineering practice and economy.

OPTIMA will therefore prove technical feasibility of implementing in-line NDT within our chrome-free pre-

treatment process for lightweight alloys to provide process control and assurance that we can achieve the level

of performance required by our customers.