科研之友
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摘要
A low-temperature, atmospheric pressure helium and oxygen plasma has been used for the surface preparation of aluminum 2024 prior to adhesive bonding. The plasma converted the aluminum from a water contact angle (WCA) of 79 degrees to down to 38 degrees within 5 s of exposure, while sanding reduced the WCA to only 51 degrees. Characterization of the aluminum surface by X-ray photoelectron spectroscopy revealed a decrease in carbon contamination from 70 to 36% and an increase in the oxygen content from 22 to 50% following plasma treatment. Similar trends were observed for sanded surfaces. Lap shear results demonstrated bond strengths of 30 +/- 2 MPa for the sanded aluminum vs. 33 +/- 1 MPa for plasma-treated aluminum, where sol-gel and primer coatings were added to the surface preparation. Following seven days of aging, wedge crack extension tests revealed cohesive failure percentages of 86, 92, and 96% for sanded, plasma-treated, and sanded/plasma-treated aluminum, respectively. These results indicate that atmospheric pressure plasmas are an attractive alternative to acid treatment or abrasion techniques for surface preparation prior to bonding.
- 出版日期2014
