Titanium adhesive joints

A number of attempts have been made to develop an alkaline peroxide anodize for titanium. However, the process requires careful control in order to provide durable adhesive joints. A recently developed sodium hydroxide anodize treatment appears to provide excellent durability and easy process control. The wedge test was used with exposure times of up... 

In biological adhesion, roughness also plays an important role. For example, roughness is routinely used to enhance cell adhesion to titanium implants that are designed to integrate with bone, such as those in hip-joint or tooth replacements. However, it is also clear that roughness does not affect the adhesion of all cells in a similar manner , and the biochemical aspects of cell responses to roughness remain a much-explored research topic (see Chapter 3c). 

The most comprehensive treatment of wet durability is Kinloch (1983). In this Minford (1983) has compared wet durabilities of joints with phenolic and epoxide-based adhesives. Joints in aluminum have been reviewed by Brewis (1983), Mahoon (1983) has dealt with titanium and Brockmann (1983) with steel. Reviews that have provided updates are those by Critchlow and Brewis (1995 and 1996), which respectively deal with the surface treatment of titanium and aluminum, and that by Armstrong (1997). A comprehensive comparison of accelerated aging and natural aging has been made by Ashcroft et al. (2001). Modeling the environmentally induced degradation of adhesively bonded joints has recently been reviewed by Crocombe et al. (2008). 

St. Clair et. al. investigated a series of maleimide and nadimide terminated polyimides and developed LARC-13 [8,9]. Changing the terminal group from maleimide to nadimide, the value of the lap shear strength of a titanium lap shear joint increased from 7 to 19 MPa [9]. They also added an elastomeric component to the adhesive formulation. The introduction of 15 wt% of a rubbery component, ATBN (amine terminated butadiene nitrile polymer) and ADMS (aniline terminated polydimethyl siloxane) enhanced the adhesive properties as follows 19 MPa to 25 MPa (ATBN) titanium T-peel strength 0.2 kN/m to 1.4... 

Adhesives and sealers can be an important part of a total corrosion protection system. Structural bonding procedures and adhesives for aluminum, polymer composites, and titanium are well established in the aerospace industry. Structural bonding of steel is gaining increasing prominence in the appliance and automotive industries. The durability of adhesive bonds has been discussed by a number of authors (see, e.g., 85). The effects of aggressive environments on adhesive bonds are of particular concern. Minford ( ) has presented a comparative evaluation of aluminum joints in salt water exposure Smith ( ) has discussed steel-epoxy bond endurance under hydrothermal stress Drain et al. (8 ) and Dodiuk et al. (8 ) have presented results on the effects of water on performance of various adhesive/substrate combinations. In this volume, the durability of adhesive bonds in the presence of water and in corrosive environments is discussed by Matienzo et al., Gosselin, and Holubka et al. The effects of aggressive environments on adhesively bonded steel structures have a number of features in common with their effects on coated steel, but the mechanical requirements placed on adhesive bonds add an additional level of complication. 

In an investigation of epoxide joints on iron and titanium using y-APS as a primer, Boerio [39] concluded that although the film structures formed by y-APS adsorbed onto the two metals were very similar, the performance of the films as adhesion promoters was very different. He concluded that the performance was determined by the orientation of the APS molecules at the oxide surface rather than by the overall structure of the film. The orientation was determined by the isoelectric point of the oxide and the pH at which the films were adsorbed onto the oxide [39,40]. A comprehensive account of the structure of APS silane films is provided by Ishida and co-workers [41]. 

At elevated temperatures where titanium alloys would be the adherend of choice, a different failure mechanism becomes important. Because the solubility of oxygen in titanium increases with temperature, the oxygen in a CAA or other oxide diffuses or dissolves into the metal, leaving voids or microcracks at the metal-oxide interface and embrittles the metal near the interface (Fig. 7). Consequently, stresses are concentrated over small areas at the interface and the joint fails at low stress levels [75,77]. Such phenomena have been observed for adherends exposed to 600°C for as little as 1 hour or 300°C for 710 hours prior to bonding [75] and for bonds using a high-temperature adhesive cured at 371°C [78] or 400°C [75]. 

CAS 2634-33-5 EINECS/ELINCS 220-120-9 Uses Microbiostat, preservative for aq. compositions such as o/w emulsions, water-based adhesives, latexes, emulsion paints, casein and rosin disps., textile spin-finish sol ns., pesticides, aq. slurries, inks, titanium dioxide slurries, tape joint compds., leather processing sol ns. preservation of fresh animal hides and skins food pkg. adhesives, paper food-contact slimicide... 

The thermal and dynamic mechanical behaviors of triblock copolymers with a styrene/isoprene/styrene architecture were investigated in order to understand their adhesive properties. Both copolymer free films and films bonding together two titanium alloy plates were found to have thermal and mechanical response that was strongly dependent on joint preparation. Microphase separation in the melts of these triblock materials was felt to contribute to the observed phenomena namely, the presence of residual stresses in thin films which had been cooled while under high pressure. 

When high-impact resistance is needed, bioceramic materials such as hydroxyapatite can be coated by plasma spraying on to metals like titanium. Plasma-sprayed calcium phosphate coatings on to steel pins, when used with implants, greatly reduce pain experienced in hip joints. Bone adhesion is also improved [68,69],... 

Titanium and its alloys have many biomedical applications due to their high strength and corrosion resistance, and are commonly incorporated in replacement hip joints and items such as bone pins [1]. Porous Ti foams have been explored for biomedical uses due to their enhanced adhesion to host tissue [15]. Surface-treatment of Ti and Ti alloys to enhance material properties, such as wear resistance, in a biomedical context has been examined [16]. In addition, titanium nitride-based materials could potentially serve as coatings for biomedical implants [17]. NiTi-based shape memory alloys are attractive candidates for biomedical materials due to their shape retention and pseudoelasticity, however, manufacturing and processing these memory alloys for biomedical apphcations is typically not straightforward [18]. 

More related information on titanium adherends can be found in Chapters 6 and 8 in this volume, and the chapter by Mahoon on the durability of titanium structural joints in Durability of Structural Adhesives. ( 36)... 

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