Titanium adhesive bonding
In the past, Russian submarines' hulls were completely made of titanium because the non-magnetic nature of the material went undetected by the defense technology at that time.
[5] Silicon carbide particles are typically in the 20 to 50 micron range with texturing occurring at a faster pace than alumina.
[5] When applied to commercially pure titanium material they will stress relieve the assembly, typically after welding, and create a satin-like finish perfect for laser marking of labels.
Surface roughness measured using Ra, Sa and Sdr is used to characterize the media application and the adhesive bonding strength.
The roughened surface is rinsed with process water or an alkaline cleaner and is often sealed with a primer application like Silane A-187 or alkoxide.
Laser roughening of titanium surfaces for epoxy bonding is a good option when abrasives and chemical agents are restricted in the manufacturing area.
Neodymium doped yttrium aluminum garnet (Nd:YAG), CO2, green, femtosecond lasers can be used depending on the workpiece and adhesion requirements.
Laser roughening of grade 5 titanium will show that the vanadium will segregate to the bulk of the alloy and appear at the surface with an increased oxygen level.
Dimples created by multiple laser pulses increase the surface area for adhesion, but the center of the topography will have reduced oxide formation because of the laser-induced plasma.
[9] Depending on the grade of titanium and the adhesive used, the laser parameters of power, frequency, and pattern can be tailored to the loading requirements and the aforementioned surface elemental beneficial conditions.
Prior to these treatments a solvent degreaser should be used with an alumina grit blast to remove unwanted oxides on the surface.
A 1982 study at the Naval Air Development Center compared 11 etchant, chemical and anodizing preparations on grade 5 titanium samples.
[6] When used on Grade 5 titanium it will produce an oxide layer 17.5 nm thick and a surface roughness of 3.4 um total height profile (Rt).
In the Review of preparation for Ti, Critchlow and Brewis state that the 10 volt anodize showed better durability results.
[7] The pores and whiskers produced can be penetrated by selecting a low viscosity adhesive, like a 3M 1838 epoxide resin or an Epo-Tek 301 epoxy.
[7] It is recommended to degrease the titanium surface and remove any corrosion by way of sanding and/or grit blasting prior to application.
