Effect of Processing Conditions on Adhesion Performance of a Sol–Gel Reinforced Epoxy/Aluminum Interface

Liu, Jiong; Chaudhury, Manoj K.; Berry, Douglas H.; Seebergh, Jill E.; Osborne, Jason W.; Blohowiak, Kay Y.

doi:10.1163/156856108x312635

Cited by 8 publications

(4 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The previous studies performed in our laboratory show that the highest increase in adhesion occurs when the gel is cured at room temperature for 75 min. In our current study, we do not observe buckling for room temperature cured films until a minimum of 3 h is passed since the coating step.…”

Section: Resultsmentioning

confidence: 75%

“…It is well-known that the strength of any adhesive promoted by a sol−gel coating in an humid environment is of paramount importance to various industrial applications. As mentioned above, Liu et al , investigated the adhesive performance of epoxy/Boegel EPII/aluminum joints under wet conditions. The overall conclusion of these studies is that water decreases the durability of the joint, thus decreasing its threshold fracture energy.…”

Section: Resultsmentioning

confidence: 99%

“…At this low temperature cure, however, it is likely that the sol−gel film is not fully cross-linked; residual hydroxyl groups may remain. Previous studies in our lab using a model epoxy adhesive elucidated that the fracture energies of the sol−gel reinforced joints are strong functions of the curing history , in both dry and wet and environments. This suggests that the performance of the sol−gel is a function of the degree of cross-linking within the film.…”

Section: Introductionmentioning

confidence: 98%

See 2 more Smart Citations

Determination of the Modulus of Thin Sol−Gel films Using Buckling Instability

Longley

Chaudhury

2010

Macromolecules

Self Cite

View full text Add to dashboard Cite

Buckling instabilities have been used to estimate the elastic modulus of thin sol-gel films. The sol-gel films (65-400 nm) were coated on elastomeric supports, which were then subjected to a compressive strain imposed directly or as a result of thermal stresses generated during the curing cycle. Atomic force and optical microscopies were used to characterize the buckling wavelength, and electron microscopy was used to estimate the thickness of the films. Elastic modulus was calculated using the classical buckling theory. This procedure, which was demonstrated previously by others starting with the systematic studies of Stafford et al. (Nature Mater. 2004, 3, 545-550), proves to be an effective way of determining the elastic modulus of thin films. The technique is used to study the effects of the concentration of the chemical precursors, curing temperature, and the duration of cure and humidity on the moduli of sol-gel films, which provide valuable information about its performance when used as an adhesion promoter.

show abstract

Section: Resultsmentioning

confidence: 75%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

See 1 more Smart Citation

Determination of the Modulus of Thin Sol−Gel films Using Buckling Instability

Longley

Chaudhury

2010

Macromolecules

Self Cite

View full text Add to dashboard Cite

show abstract

“…[7][8][9][10][11] By fine tuning synthesis and processing parameters, hybrid thin films can be developed to exhibit high-performance adhesion capable of withstanding in-service stresses and degradation from environmental stresses.…”

Section: Introductionmentioning

confidence: 99%

Hybrid coupling layers for bulk metallic glass adhesion

Yang

Dauskardt

2013

J. Mater. Res.

View full text Add to dashboard Cite

Solutions to the technical challenge of bonding and joining bulk metallic glasses have long been sought after due to the exceptional property sets displayed by this class of engineering materials. Here, we demonstrate the ability to deposit a compositionally and functionally graded hybrid coupling layer using sol-gel processing methods to promote adhesion at the metallic glass-epoxy interface. In this study, we fine-tune the molecular composition by varying the sol Zr:Si ratio, altering film properties that consequently influence crack path selection at the interface. When optimized, up to 3-fold improvements in the adhesive/cohesive properties of these structural bond lines can be attained, with the highest G C values correlating with cohesive cracking through the hybrid. We also demonstrate the ability of these hybrid structures to significantly reduce the influence of moisture-assisted degradation as evidenced by reductions in crack growth rates of over two orders of magnitude and increased threshold limits.

show abstract

Bond strength of hybrid sol–gel coatings with different additives

2012

View full text Add to dashboard Cite

Printing inks typically consist of a functional component dispersed within a low-viscosity resin/solvent system where interparticle interactions would be expected to play a significant role in dispersion, especially for the high-aspect-ratio nanocarbons such as the graphite nanoplatelets (GNPs). Rheology has been suggested as a method for assessing the dispersion of carbon nanomaterials in a fluid. The effects of phase volume of ammonia plasma-functionalized GNPs on a near-Newtonian low-viscosity thermoplastic polyurethane (TPU) resin system have been studied using shear and quiescent oscillatory rheology. At low concentrations, the GNPs were well dispersed with a similar shear profile and viscoelastic behavior to the unfilled TPU resin, as viscous behavior prevailed indicating the absence of any long-range order within the fluid. Particle interactions increased rapidly as the phase volume tended toward maximum packing fraction, producing rapid increases in the relative viscosity, increased low shear rate shear thinning, and the elastic response becoming increasingly frequency independent. The nanoscale dimensions and high-aspect-ratio GNPs occupied a large volume within the flow, while small interparticle distances caused rapid increases in the particle-particle interactions to form flocculates that pack less effectively. Established rheological models were fitted to the experimental data to model the effect of high-aspect-ratio nanocarbon on the viscosity of a low-viscosity system. Using the intrinsic viscosity and the maximum packing fraction as fitting parameters, the Krieger-Dougherty (K-D) model provided the best fit with values. There was good agreement between the estimates of aspect ratio from the SEM images and the predictions of the aspect ratio from the rheological models. The fitting of the K-D model to measured viscosities at various phase volumes could be an effective method in characterizing the shape and dispersion of high-aspect-ratio nanocarbons.

show abstract

Effect of Processing Conditions on Adhesion Performance of a Sol–Gel Reinforced Epoxy/Aluminum Interface

Cited by 8 publications

References 22 publications

Determination of the Modulus of Thin Sol−Gel films Using Buckling Instability

Determination of the Modulus of Thin Sol−Gel films Using Buckling Instability

Hybrid coupling layers for bulk metallic glass adhesion

Bond strength of hybrid sol–gel coatings with different additives

Contact Info

Product

Resources

About