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Environmentally friendly anodising process for structural bonding of titanium
Author(s) -
RicoOller B.,
Mertens T.,
Kolb M.,
Wehr J.,
Zheludkevich M.
Publication year - 2016
Publication title -
materialwissenschaft und werkstofftechnik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.285
H-Index - 38
eISSN - 1521-4052
pISSN - 0933-5137
DOI - 10.1002/mawe.201600515
Subject(s) - materials science , scanning electron microscope , anodizing , titanium , metallurgy , oxide , chemical engineering , transmission electron microscopy , durability , electrolyte , titanium alloy , composite material , alloy , chemistry , nanotechnology , aluminium , electrode , engineering
This paper evaluates the applicability of two wet‐chemical treatments for structural bonding of titanium alloy Ti6Al4V. The anodising processes, NaTESi and N4‐Process, are based on electrolytes containing sodium hydroxide and complexing agents, but while NaTESi process contains ethylenediaminetetraacetic acid, a particularly hazardous chemical, N4‐Process is a REACh compliant electrolyte. Scanning electron microscopy and transmission electron microscopy were employed to evaluate the oxide layer formed after the anodising processes. The long‐term durability and the resultant adhesion properties on titanium were assessed by means of floating‐roller‐peel test. Both investigated anodising processes lead to oxide layers revealing a highly porous nanostructure (thickness between 150–600 nm) according to scanning electron microscopy and transmission electron microscopy analyses. The mechanical tests lead to negligible differences between processes, performing higher peel resistance when compared to only alkaline etched samples, especially after 1000 hours ageing at 50 °C and 95 % relative humidity. The results indicate that N4‐Process is a promising treatment to enhance the long‐term durability of bonded titanium joints, especially under hot and wet conditions.