Bonding alloys

Plutonium-noble metal compounds have both technological and theoretical importance. Modeling of nuclear fuel interactions with refractory containers and extension of alloy bonding theories to include actinides require accurate thermodynamic properties of these materials. Plutonium was shown to react with noble metals such as platinum, rhodium, iridium, ruthenium, and osmium to form highly stable intermetallics. 

Plutonium-noble metal compounds have both technological and theoretical importance. Modeling of nuclear fuel interactions with refractory containers and extension of alloy bonding theories to include actinides require accurate thermodynamic properties of these materials. Plutonium was shown to react with noble metals such as platinum, rhodium, iridium, ruthenium, and osmium to form highly stable intermetallics. Vapor pressures of phases in these systems were measured by the Knudsen effusion technique. Use of mass spectrometer-target collection apparatus to perform thermodynamic studies is discussed. The prominent sublimation reactions for these phases below 2000 K was shown to involve formation of elemental plutonium vapor. Thermodynamic properties determined in this study were correlated with corresponding values obtained from theoretical predictions and from previous measurements on analogous intermetallics. 

BEARING, SLEEVE - A cylindrical plain bearing used to provide radial location for a shat, which moves axially. Sleeve bearings consist of one or more layers of bearing alloys, bonded to a steel backing. 

HOC = high gold-containing (Au + Pt metals > 75 wt%, Pt metals 1 = soft, 2 = medium hard, 3 = hard, 4 = extra hard, c = ceramic alloy (bonding with ceramic is possible). 

Figure 13. XPS titanium 2p photopeak of failed lap shear sample of titanium alloy bonded with polyimide adhesive solvent cast from (a) DMAC solution and from (b) diglyme solution (22).

The failure surfaces produced following tests of lap shear or wedge samples of titanium alloy bonded with epoxy depended on the surface pretreatment (34). Simple add etching of the adherend produced primarily interfacial failure between the oxide and epoxy whereas chromic acid anodization of the adherend resulted in failure within the oxide layer as in the case discussed above. 

The often used FPL etdi of an aluminum-lithium alloy bonded with polysulfone leads to interfacial (at the metal oxide/polymer interface) failure (38) which is a surprisingly uncommon type of failure. The results leading to this assignment are shown as XPS C Is and O Is narrow scan spectra in Figure 15. This definitive assignment of failure mode is based on the fact that one failure surfece has an oi gen photopeak similar to the pretreated adherend before bonding and the other failure surfece has an 0 gen photopeak similar to the adhesive. 

For tool manufacture, the hard boron nitride alloy composites have to be bonded to refractory metals or hard steel alloys. Interlayers used for this purpose should have an adapted expansion coefficient and form mixed phases with the alloy-bonded boron nitride and the metallic substrate. It also should withstand the high temperatures developed during metal working. Thus, TiC [88] or Co/Ni [89] are used in these interlayers. On the other hand, the alloy... 

Figure 6 Strenglhs of lap joints in aluminium alloy bonded with a vinyl phenolic adhesive on exposure to wet air at 50°C. O Aged at 50% r.h. and 100% rJi. A aged at 100% r.h. for 5000 h, then at 50% r.h. for a further 5000 h [30]. Crown Copyright.

Figure 30 Variation of the lap-shear strength as a fnnction of the ageing time in flowing air for TU-2 titanium alloy bonded with polyimide precursors 30. Assemblies aged at 260°C lap-shear strength measnred at room temperature (a) and at 260°C (b). Assemblies aged at 300°C lap-shear strength measured at room temperature (c) and at 300°C (d).

Figure 32 Variation of the lap-shear strength as a function of the ageing time in flowing air for TU-2 titanium alloy bonded with Nolimid 380 polyimide precursors.

Figure XIV-11 shows the fuel subassembly of the 4S. The fuel element (fuel pin) consists of fuel slugs of U-Zr alloy, bonding sodium, cladding tube, and plugs at both ends. A gas plenum of an adequate length is located at the upper region of the fuel slugs.

The TBCs deposited by plasma spraying consist (adjacent to the metallic substrate Inconel, Hastelloy, Ti6Al4V) of a dense MCrAlY (M = Ni, Co) alloy bond coat which is laid down by low-pressure plasma spraying (LPPS), followed by a porous stabilized zirconia top coat in the thickness range of 300 to lOOOgm (Cernuschi et al., 2004), as shown schematically in Figure 7.39. During operation. 

Table 4.14 Effect of surface pretreatment on the initial strength of 6A1-4V-Ti alloy bonded with a hot-cured epoxy adhesive [136]...

Table 4.16 Effect of pre treatment on the initial single lap-shear strength of clad aluminium alloy bonded with various two-part adhesives [147]...

Figure 9.32 Variation of the lap-shear strength asafunc-tion of the aging time in flowing air for TU-2 titanium alloy bonded with Nolimid 380 polyimide precursors. The strength of adhesion is measured at the aging temperatures (a) 340, (b) 377, (c) 400, and (d) 450 °C.

Ohno H, Endo K, Hashimoto M. New mechanical retention method for resin and gold alloy bonding. Dent Mater. 2004 20(4) 330—337. 

The general conclusion reached was that aqueous homogeneous reactors are potentially very low-cost plutonium producers however, considerable development work remains before large-scale reactors can be constructed. The major problem is due to the corrosiveness of the relatively concentrated uranyl sulfate solutions used in such reactors, which requires that all the equipment in contact with high-temperature fuel be made of titanium, or carbon-steel lined, or clad with titanium. The development of suitably strong titanium alloys, bonding methods, or satisfactory steel-titanium joints has not yet proceeded sufficiently to consider the construction of full-scale plutonium producers. Alternate approaches, such as the addition of Li2S04 to reduce the corrosiveness of stainless steel by the fuel solution (see Chap. 5), show promise but also require further development. 

To achieve proper solder joints, the molten metal must be in direct contact with the metal surface to be joined. For bonding to occur, some form of interaction must take place at the interface. In the case of Sn-Pb solders bonding to Cu, Sn must diffuse into the Cu surface, forming the intermetallic compounds CusSn and CueSus with the bulk of the solder alloy bonded to this layer. Solder-to-solder bonding results from alloy reacting at the liquid interfaces. 

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