Ion beam sputter coating in combination with sol-gel dip coating of Al alloy tube inner walls for corrosion and biological protection

Aluminium alloy AlCuMg is an alloy with high mechanical strength and fracture toughness, but it suffers from poor corrosion resistance and friction behaviour. With a combined process of sol-gel deposition of zirconium oxide and a top coating of diamond-like carbon formed by ion beam sputtering with a movable conical sputter target inside the tube, the inner walls of AlMgCu tubes were homogeneously coated with a duplex coating with high resistance against corrosion in chloride solution. When Ag was added to the carbon sputter target, a DLC coating that contained Ag was obtained. Microbial tests showed that the coating is effective against pathogenic E. coli bacteria.