SurTec 650 is a chromium(VI)-free trivalent passivation for aluminium. The liquid concentrate delivers an excellent corrosion protection, comparable with the corrosion protection of a hexavalent passivation.
SurTec 650 is suitable for alloyed and casted aluminium and pretreatment before laquering, powder coating and gluing. It is easy to handle in immersion, spray and wipe application and produces an iridescent, faintly blue to tan and visible layer.
SurTec 650 meets or exceeds MIL-DTL-81706 and MIL 5541 for bare corrosion (336 h in NSS per ASTM B-117, respectively, DIN 50021 SS) and has a low contact resistance (< 0.8 mOhm/cm2). It is also heat resistant up to 100 °C (212 °F) with minimal loss in corrosion resistance.
US-patents 6,375,726; 6,511,532; 6,521,029; 6,527,841 are applied.