Copper substrate

Under micro-discontinuous chromium coatings, copper undercoats improve corrosion resistance. On non-conductors, especially on plastic substrates, copper is often applied before nickel-chromium plating over the initial electroless copper or nickel deposit in order to improve ductility and adhesion, e.g. as tested by the standard thermal-cycling test methods ... 

Copper(II) triflate has also been used for the carbenoid cyclopropanation reaction of simple olefins like cyclohexene, 2-methylpropene, cis- or rran.y-2-butene and norbomene with vinyldiazomethane 2 26,27). Although the yields were low (20-38 %), this catalyst is far superior to other copper salts and chelates except for copper(II) hexafluoroacetylaeetonate [Cu(hfacac)2], which exhibits similar efficiency. However, highly nucleophilic vinyl ethers, such as dihydropyran and dihydrofuran cannot be cyclopropanated as they rapidly polymerize on contact with Cu(OTf)2. With these substrates, copper(II) trifluoroacetate or copper(II) hexafluoroacetylaeetonate have to be used. The vinylcyclopropanation is stereospecific with cis- and rra s-2-butene. The 7-vinylbicyclo[4.1.0]heptanes formed from cyclohexene are obtained with the same exo/endo ratio in both the Cu(OTf)2 and Cu(hfacac)2 catalyzed reaction. The... 

Copper substrates are commonly bonded with epoxy adhesives in the microelectronics and marine industries. Compared to aluminum substrates, copper when bonded with epoxy adhesives provides lower initial strength. Depending on the adhesive and the type of test used, this can be as much as 50 percent lower. Similar to aluminum joints, copper joints bonded with epoxy adhesives can show poor durability in moist environments unless the interface is protected. 

Fig. 33. Some possible positions of a nitrogen molecule physically adsorbed on single crystal copper surfaces. (Projections are constructed to scale in directions normal and parallel to the substrate. Copper atoms are schematically indicated as rigid close packed spheres and nitrogen molecules as spherical pairs.) [After Rhodin, J. Am. Chem. Soc. 72, 5691 (1950).]...

Compounds (20) and (21) undergo electrochemical oxidation to give films of poly(2-methyl-8-quinolinol) and poly(8-quinolinol) on a variety of metal substrates. Copper(II) can be com-plexed from aqueous media, but cobalt(II) requires an organic medium. X-ray photoelectron spectroscopy shows the copper(II) complex of films derived from (20) to be complexed to both N and O and also shows that water is absent from the primary coordination sphere. However, for cobalt(II) on the polymer derived from (21), water is present in the primary coordination shell. 

However, both cases should result in microstress, while macrostress should depend basically on the mode of coalescence of two-dimensional grains into a continuous film. Such an effect could be replicated on layers piling up on top of each other. This is supported by experiments which have shown that, e.g., nickel plated on different substrates (copper-plated steel, beryllium-copper, and silver-plated steel) exhibits different internal stress which extends into layers 10 -10 nm away from the substrate without any tendency to decrease. 

Textile-based energy storage devices were fabricated with PEDOTiPSS as the electrolyte, conductive yams as yam electrodes, and textile substrate. Copper-coated PBO filament yams, silver-coated PBO filament yarns, and pure stainless steel filament yams were used as yam electrodes to produce different types of devices. These charge storage devices were well integrated into textile stmcture, making them lightweight and flexible. The devices could be easily fabricated. 

Note in the table that copper-clad Invar has both variable Tg, and variable thermal conductivity depending on the volume mix of copper and Invar in the substrate. Copper has a high TCE, and Invar has a low TCE, and so the TCE increases with the thickness of the copper layers. In addition to heat transfer considerations, board material decisions must also be based on the expected stress and humidity in the application. 

In contrast to IDA-modified silica columns, less work has been carried out on silica columns modified with APA. Nevertheless, the work done by Nesterenko and Jones [70] so far indicates great potential for this chelating stationary phase. As demonstrated with the separation of various alkaline-earth and transition metals in Figure 4.76, HPCIC with aminophosphonic groups results in more evenly spaced peaks, so that simple nitric acid eluents have been used so far. Despite the high efficiency of the sihca substrate, copper tends to give a much broader peak than other metals, which is also observed using IDA-modified silica columns. 

If Eq. (in.l) is satisfied, the charge observed on the particles after detachment should be zero (isoelectric point), and the electrical component will not affect the value of the adhesive force. Experimental results show that in individual cases this condition is in fact satisfied. For example, the charge determined on removing dust from a metal substrate (copper) equals zero [70],... 

S. Chada, W. Laub, R. Foumelle, and D. Shangguan, Microstructural Evolution of Sn-Ag Solder Joints Resulting from Substrate Copper Dissolution, Proceedings of SMTA Conference, Sept 1999, p 412-418... 

In the last few years, the use of NHC-Cu complexes in catalysis has grown exponentially, particularly for the transfer of carbon and heteroatom-based nucleophiles to various electrophilic substrates. Copper-catalyzed boron and silicon transfers have recently been reported, thus expanding the scope of NHC-copper-catalyzed reactions. Notably, the design of new chiral NHC ligands has enabled the successful development of efficient C-C and C-H bond forming enantioselective reactions. 

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