Abstract
Adhesive bonding between carbon fibre reinforced plastics (CFRPs) and aluminium alloys is extensively practised to achieve optimum lightweight and reliable structures in the aerospace and automobile industries. In this research, we study pre-treatments of aluminium substrates for stronger adhesion with CFRP. An ultrasonic etching process was carried out in alkaline solutions to investigate the influence of NaOH concentration on adhesive bonding characteristics. An ultra-thin layer of acetone-diluted resin pre-coating (RPC) without hardener was then applied to the etched substrates to seal micro-cavities before adhesive bonding. The single lap shear test was used to evaluate the adhesive bond strength under different surface conditions. The topography and chemistry of treated surfaces were characterised using various surface analytical tools including optical profilometry, scanning electron microscopy and X-ray microanalysis (SEM/EDS), contact angle goniometry and X-ray photoelectron spectroscopy (XPS). Experimental results showed a maximum 91% improvement in bond strength after alkaline etching treatments, which removed the weak passive oxide layers and allowed the formation of thin hydroxide layers through aluminium-water reactions. The wettability of etched specimens was also improved, indicating by their higher surface energy values. Variations of roughness parameters and tomography under different NaOH concentrations also affected the bond strength. The RPC treatments further increased the bond strength of NaOH etched specimens by 8.4–11.6%. The surface treatments reported in this work are very simple and cost-effective for producing durable adhesive joints in industrial applications.
| Original language | English |
|---|---|
| Article number | 107478 |
| Journal | Composites Part B: Engineering |
| Volume | 178 |
| DOIs | |
| Publication status | Published - 1 Dec 2019 |
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NaOH etching and resin pre-coating treatments for stronger adhesive bonding between CFRP and aluminium alloy. / Hu, Yunsen; Yuan, Bingyan; Cheng, Fei; Hu, Xiaozhi.
In: Composites Part B: Engineering, Vol. 178, 107478, 01.12.2019.Research output: Contribution to journal › Article
TY - JOUR
T1 - NaOH etching and resin pre-coating treatments for stronger adhesive bonding between CFRP and aluminium alloy
AU - Hu, Yunsen
AU - Yuan, Bingyan
AU - Cheng, Fei
AU - Hu, Xiaozhi
PY - 2019/12/1
Y1 - 2019/12/1
N2 - Adhesive bonding between carbon fibre reinforced plastics (CFRPs) and aluminium alloys is extensively practised to achieve optimum lightweight and reliable structures in the aerospace and automobile industries. In this research, we study pre-treatments of aluminium substrates for stronger adhesion with CFRP. An ultrasonic etching process was carried out in alkaline solutions to investigate the influence of NaOH concentration on adhesive bonding characteristics. An ultra-thin layer of acetone-diluted resin pre-coating (RPC) without hardener was then applied to the etched substrates to seal micro-cavities before adhesive bonding. The single lap shear test was used to evaluate the adhesive bond strength under different surface conditions. The topography and chemistry of treated surfaces were characterised using various surface analytical tools including optical profilometry, scanning electron microscopy and X-ray microanalysis (SEM/EDS), contact angle goniometry and X-ray photoelectron spectroscopy (XPS). Experimental results showed a maximum 91% improvement in bond strength after alkaline etching treatments, which removed the weak passive oxide layers and allowed the formation of thin hydroxide layers through aluminium-water reactions. The wettability of etched specimens was also improved, indicating by their higher surface energy values. Variations of roughness parameters and tomography under different NaOH concentrations also affected the bond strength. The RPC treatments further increased the bond strength of NaOH etched specimens by 8.4–11.6%. The surface treatments reported in this work are very simple and cost-effective for producing durable adhesive joints in industrial applications.
AB - Adhesive bonding between carbon fibre reinforced plastics (CFRPs) and aluminium alloys is extensively practised to achieve optimum lightweight and reliable structures in the aerospace and automobile industries. In this research, we study pre-treatments of aluminium substrates for stronger adhesion with CFRP. An ultrasonic etching process was carried out in alkaline solutions to investigate the influence of NaOH concentration on adhesive bonding characteristics. An ultra-thin layer of acetone-diluted resin pre-coating (RPC) without hardener was then applied to the etched substrates to seal micro-cavities before adhesive bonding. The single lap shear test was used to evaluate the adhesive bond strength under different surface conditions. The topography and chemistry of treated surfaces were characterised using various surface analytical tools including optical profilometry, scanning electron microscopy and X-ray microanalysis (SEM/EDS), contact angle goniometry and X-ray photoelectron spectroscopy (XPS). Experimental results showed a maximum 91% improvement in bond strength after alkaline etching treatments, which removed the weak passive oxide layers and allowed the formation of thin hydroxide layers through aluminium-water reactions. The wettability of etched specimens was also improved, indicating by their higher surface energy values. Variations of roughness parameters and tomography under different NaOH concentrations also affected the bond strength. The RPC treatments further increased the bond strength of NaOH etched specimens by 8.4–11.6%. The surface treatments reported in this work are very simple and cost-effective for producing durable adhesive joints in industrial applications.
KW - Adhesive bonding
KW - Alkaline etching
KW - Aluminium alloy
KW - CFRP
KW - Resin pre-coating
UR - http://www.scopus.com/inward/record.url?scp=85072551251&partnerID=8YFLogxK
U2 - 10.1016/j.compositesb.2019.107478
DO - 10.1016/j.compositesb.2019.107478
M3 - Article
VL - 178
JO - COMPOSITES PART B-ENGINEERING
JF - COMPOSITES PART B-ENGINEERING
SN - 0961-9526
M1 - 107478
ER -