Abstract
Due to potential energy and cost savings benefits, adhesive joining has been recently considered for heating, ventilation, air conditioning, and refrigeration (HVAC&R) systems. HVAC adhesive bonding requires cost-effective and adequate surface preparations of adherents. This article investigates the use of abrasion, traditional single-beam laser, and a laser-interference technique as surface preparations of copper surfaces. Surface morphology is characterized using scanning electron microscopy (SEM) and atomic force microscopy (AFM). Effective submicrometer peak-to-valley structuring with a periodicity of ∼2.7 (Formula presented.) was demonstrated for laser-interference processing. Single-lap shear tests were conducted for 89 joints made with bondline thicknesses of 0.15 and 0.3 mm. Data on process variables and measured variables included open-time, bond length, maximum load, displacement at failure, shear lap strength, and failure mode. A statistical analysis was conducted on each lot to determine the lower limit with 95% confidence intervals for displacements at failure and shear lap strengths. A comparison is presented between the properties of laser-structured joints with respect to those prepared by abrasion, which is considered the baseline surface preparation technique. Based on this comparison, one single-beam laser technique and two laser-interference techniques were shown to exhibit vastly superior performance over the joints made with abraded specimens.
| Original language | English |
|---|---|
| Pages (from-to) | 226-246 |
| Number of pages | 21 |
| Journal | Science and Technology for the Built Environment |
| Volume | 32 |
| Issue number | 2 |
| DOIs | |
| State | Published - 2026 |
Funding
This project is funded through Buildings Energy Efficiency Frontiers & Innovation Technologies. This work was performed for the project “Adhesive Bonding of Aluminum and Copper in HVAC&R Applications” sponsored by the Building Technologies Office, Office of Energy Efficiency and Renewable Energy, U.S. Department of Energy under contract DE-AC05–00OR22725, Oak Ridge National Laboratory, managed and operated by UT-Battelle, LLC. The authors thank Antonio Bouza (DOE BTO HVAC, Water Heating, and Appliances Technology Manager) for his support, Michael Littleton for performing laser structuring and adhesive bonding, Dr. Donald Erdmann III and Christina Austin of ORNL for conducting single-lap shear testing, and Dr. Dennis Ngo of 3M, Inc., for providing the adhesive, adhesive bonding procedures, and surface preparation procedures for adhesive joining.