TY - JOUR
T1 - Surface characterization and adhesion of black-oxide-coated copper substrate
T2 - Effect of surface hardening processes
AU - Lebbai, Mohamed
AU - Kim, Jang Kyo
AU - Szeto, W. K.
AU - Wu, Jingshen
N1 - Funding Information:
This project was supported by the Research Grant Council of Hong Kong Special Administration Region (Project number HKUST6211/01E). QPL Ltd. Hong Kong provided partial financial support to M. L. and supplied the black oxide coated substrates. Loctite Hong Kong Ltd. provided the resins. Most experiments were carried out with the technical supports from the Material Characterization and Preparation Facilities (MCPF) and EPack Lab of HKUST.
PY - 2004
Y1 - 2004
N2 - The effects of surface-hardening processes on the changes in surface characteristics and adhesion of black copper oxide substrate with epoxy resins are studied. Various techniques, namely SEM, XPS, AFM, XRD, Auger electron spectroscopy, contact angle goniometry, D-SIMS and RBS, were used to identify the changes in surface characteristics. Dense, fibrillar cupric oxide crystals characterized the as-deposited oxide coating with high surface roughness. The surface-hardening process flattened and consolidated the fibrils without changing the compositional and thermodynamic characteristics of the coated surface. The surface-hardening process reduced the total thickness of copper oxide by approximately 50-150 nm. The reduction in oxide thickness was not a predominant factor for the reduced bond strength of the surface-hardened coating. The bond strengths of both the as-deposited and surface-hardened black oxide coatings increased with oxidation time, until saturation at about 120-150 s. For the as-deposited oxide coating, mechanical interlocking, high wettability and resistance to surface contamination are the three major sources for improved adhesion, amongst which the enhanced mechanical interlocking provided by the fibrillar cupric oxide is the most important. Surface hardening reduced the efficiency of mechanical interlocking mechanism. There was close functional dependence between the button-shear strength and surface characteristics, such as surface roughness, coating thickness and surface free energy.
AB - The effects of surface-hardening processes on the changes in surface characteristics and adhesion of black copper oxide substrate with epoxy resins are studied. Various techniques, namely SEM, XPS, AFM, XRD, Auger electron spectroscopy, contact angle goniometry, D-SIMS and RBS, were used to identify the changes in surface characteristics. Dense, fibrillar cupric oxide crystals characterized the as-deposited oxide coating with high surface roughness. The surface-hardening process flattened and consolidated the fibrils without changing the compositional and thermodynamic characteristics of the coated surface. The surface-hardening process reduced the total thickness of copper oxide by approximately 50-150 nm. The reduction in oxide thickness was not a predominant factor for the reduced bond strength of the surface-hardened coating. The bond strengths of both the as-deposited and surface-hardened black oxide coatings increased with oxidation time, until saturation at about 120-150 s. For the as-deposited oxide coating, mechanical interlocking, high wettability and resistance to surface contamination are the three major sources for improved adhesion, amongst which the enhanced mechanical interlocking provided by the fibrillar cupric oxide is the most important. Surface hardening reduced the efficiency of mechanical interlocking mechanism. There was close functional dependence between the button-shear strength and surface characteristics, such as surface roughness, coating thickness and surface free energy.
KW - Adhesion
KW - Copper oxide
KW - Failure mode
KW - Surface characteristics
KW - Surface hardening process
UR - http://www.scopus.com/inward/record.url?scp=3142711412&partnerID=8YFLogxK
U2 - 10.1163/1568561041257513
DO - 10.1163/1568561041257513
M3 - Article
AN - SCOPUS:3142711412
SN - 0169-4243
VL - 18
SP - 983
EP - 1001
JO - Journal of Adhesion Science and Technology
JF - Journal of Adhesion Science and Technology
IS - 9
ER -