Adhesive Force Improvement of Lamination with 18-8 Stainless Steel and CFRP Separately Irradiated by Electron Beam Prior to Assembly and Hot-Pressing

Abstract

Adhesive 2-layer lamination joints of 18mass%Cr-8mass%Ni austenite stainless steel and carbon ber reinforced polymer (18-8/CFRP) were prepared using a new adhesion method consisting of applying low dose of 0.13 MGy of homogeneous low energy electron beam irradiation (HLEBI) to connecting surfaces of the 18-8 and CFRP prior to assembly and hot-pressing in vacuum under atmospheric pressure of about 1 Pa for 2 h at 401 ± 0.5 K. Although untreated 18-8/CFRP joint exhibited decent adhesion by hot-pressing, application of 0.13 MGy HLEBI dose apparently improved the adhesive force of peeling resistance ( o F p ) of the 18-8/CFRP joint 145% at median accumulative peeling probability (P p = 0.50) from 18.9 to 27.4 Nm −1. In addition, the statistically lowest o F p for safety design (F s at P p = 0) iterated by the 3-parameter Weibull equation was raised from zero for the untreated to 5.2 Nm −1 for the 0.13 MGy samples indicating increased reliability by the HLEBI. The higher adhesive strength induced by HLEBI was explained by results of XPS (X-Ray Photoelectron Spectroscopy) observations of the peeled surface of 18-8 side of lamination with and without 0.13 MGy-HLEBI. 0.13 MGy-HLEBI slightly increased the number of C=C bonds instead of slightly decreasing the numbers of C-C, C-H and O=C-O bonds near 18-8/CFRP interface. In addition, both increasing oxygen atoms and decreasing hydrogen atoms strongly attributed to bonding force at interface of epoxy of 18-8/CFRP. Since the experimental data showed the optimum HLEBI dose was about 0.13 MGy, above which at 0.13 MGy the o F p began to drop, carefulness in optimization was highly recommended when applying in industry to insure safety.

Adhesive Force of Laminations of Titanium Untreated and Polycarbonate Homogeneously Irradiated by Low Potential Electron Beam Prior to Assembly and Hot-Press

“…Both Ti and PC peeled connecting surfaces were scanned for elements C, H, O and Ti by using X-ray photoelectron spectroscopy (XPS: Quantum 2000, ULVAC Co., JAPAN) 15) for the 0.30 MGy and untreated samples after fracture. Narrow scans were performed for the C (1s) and O (1s) signals.…”

“…6) Due to these constraints, high strength adhesive laminations are dif cult to attain. Homogeneous low energy electron beam irradiation (HLEBI) has a successful treatment for improving polymer-polymer [7][8][9][10][11][12] and metal-polymer [13][14][15] laminations. These effects are mainly caused by surface energy induced by the irradiation with the formation of active terminated atoms with dangling bonds creating chemical bonds between the metal and polymer.…”

An Aluminum/Polycarbonate (Al/PC) Joint by Homogeneous Low Voltage Electron Beam Irradiation (HLEBI) to PC Prior to Lamination Assembly and Hot-Press

“…15) For Al/epoxy CFRP joints applying 0.22 MGy HLEBI is reported to boost shear strength, τ 45% at low fracture probability, P s = 0.06. 13) These effects are mainly caused by surface energy induced by the irradiation with the formation of active terminated atoms with dangling bonds creating chemical bonds between the metal and polymer.…”

“…However, HLE-BI to PC prior to hot-press created a decent mean adhesive force of peeling resistance ( o F p ) of the Al/PC joint. HLEBI has a successful track record for improving polymer-polymer [10][11][12] and metal-polymer [13][14][15] joints. For polymer-polymer joints, polyimide/Te on (PI/PTFE) layered lms have been successfully fabricated by EB irradiation; 11) while applying 0.50 MGy EB dose increased adhesive bond strength between PET lms and acrylic adhesive.…”