THE EFFECT OF SODIUM-HYDROXIDE ANODIZATION ON THE DURABILITY OF POLY(ETHERKETONETHERKETONEKETONE) ADHESIVE BONDING OF TITANIUM

The use of thin-film thermoplastic bonding to metals is an attractive option for future manufacturing. However the process has to be develop ed and the durability of these joints investigated. Grit blasting and Sodium Hydroxide Anodization (SHA) are used to modify titanium alloy ( Ti-6A1-4V) specimens. The design of experiments used two voltages (10 and 15 V) and times (IS and 30 min) to create different surface morpho logies. Titanium rods were then joined using poly ether ketone ether k etone ketone (PEKEKK) in thin-film form. The joined specimens were ten sile tested before and after soaking in Ringer's solution (38 degrees C) up to a period of six months. The surfaces were characterized using Profilometry, Scanning Electron Microscopy (SEM), and Energy Dispersi ve Spectroscopy (EDS). Joints created from anodization at 10 V for 30 min had very high initial tensile strengths of 134 MPa. Large diameter pores (approximate to 100 nm) in the oxide were more attractive than smaller (approximate to 30 nn) ones for PEKEKK-Ti adhesive joints unde r Ringer's solution soak. The adherends anodized at 15 V for 15 min re tained 41% of their initial strengths after a soak period of six month s, while the non-anodized joints retained only 6% of their initial str engths during the same period. The performance of anodized PEKEKK-Ti j oints clearly exceeds non-anodized PEKEKK-Ti and other thermoset based joints for immersion soak periods to six months. (C) 1997 Elsevier Sc ience Limited.