Surface Modification Using MAPLE Technique for Improving the Mechanical Performance of Adhesive Joints

Abstract

The adhesive bonds that ensure the appropriate mechanical properties for metal joining imply the surface chemical and wetting modification characteristics of the substrates. In this work, matrix-assisted pulsed laser evaporation (MAPLE) was used for the surface modification of Al via the deposition of two chemical compounds, polyvinyl alcohol (PVA) and triethanolamine (TEA), from frozen aqueous solutions. The deposition of the TEA and PVA layers was evidenced by FT-IR, SEM, and AFM analysis. The contact angle measurements evidenced the change in the hydrophilicity of the surface and surface free energies. The performance of the commercial silyl-based polymer adhesive Bison Max Repair Extreme Adhesive® was evaluated by tensile strength measurements. This method led to a change in tensile strength of 54.22% in the case of Al-TEA and 36.34% for Al-PVA compared with the control. This study gives preliminary insights into using MAPLE, for the first time in adhesive applications, as a pretreatment method for Al plates for adhesive bonding reinforcement.

Surface pre-treatment of aluminum alloy for mechanical improvement of adhesive bonding by maple-assisted pulsed laser evaporation technique

“…To irradiate the target (practically, the frozen aqueous solutions) a Continuum Company's Surelite II pulsed Nd:YAG laser system was used, operating at a wavelength of 266 nm, with a pulse of 6 ns and a repetition rate of 10 Hz. Based on previous works on MAPLE deposition of polymers or other sensitive compounds, 25,26 as well as on the necessity to have full coverage of the 1 cm 2 areas from the Al plate, the number of pulses used was 72.000, while the chosen uence that could ensure no chemical modication was 350 mJ cm −2 . The target holder was continuously rotated (20 rpm) throughout the irradiation process to prevent the target from overheating.…”

“…The calculations for SFE expressed as mJ m −2 for whole specimens were based on the standard values for SFE, dispersive (g D ), and polar component (g P ) for two liquids, namely water and methylene iodide (Table 2) using the g = g D + g P equation. 25,33 In solid-liquid interactions, these two components, g D , and g P can be determined based on contact angle measurements as described in a previous work. 25 By determining the SFE of a solid material, one can predict the behavior of any liquid on its surface.…”

“…25,33 In solid-liquid interactions, these two components, g D , and g P can be determined based on contact angle measurements as described in a previous work. 25 By determining the SFE of a solid material, one can predict the behavior of any liquid on its surface. This predictive capability arises from the insight gained into the interactions between the material's surface and various liquids, enabling forecasts regarding wetting behavior, adhesion, and other surface-related phenomena.…”

“…22 In term of adhesion, MAPLE ensures superior adhesion of the lm to the substrate, controllable thickness of the deposited layer (from few tens of nanometers to 1 micron) following the exact pattern of the substrate. [23][24][25] In one of our previous studies, 25 the mechanical performance of adhesive joints between Al substrates was enhanced by modifying their wettability through the deposition of triethanolamine (TEA) and polyvinyl alcohol (PVA, Mn = 124 000 g mol −1 ) using MAPLE technique. This approach resulted in a 54.22% increase in tensile strength for Al plates modied with TEA and a 36.34% increase for those modied with PVA compared to the unmodied substrates.…”

Monitoring of the curing process and thermal failure of adhesive-bonded structures based on damping measurement using quantitative electromechanical impedance

“…While these methods enable monitoring of the adhesive curing process, they predominantly concentrate on the adhesive material itself rather than the bonding structure. The performance of adhesives in practical applications is also strongly influenced by the connection type, loading conditions and the state of the contact surfaces [15][16][17]. Note that the abovementioned methods often involve destructive approaches that may cause irreversible damage to the cemented structure and cannot provide a comprehensive understanding of the curing and deterioration process of the adhesive [18].…”