Metal-bis-

FI4312 Structural integrity of Bi-metallic components Mr. Claude Faidy Electricity de France... 

Characteristics of a bi-metallic thermal relay The thermal characteristics are almost the same as those of an induction motor. This makes them suitable for protecting a motor by making a judicious choice of the right range for the required duty. (See Figure 12.11 for a typical thermal overload relay and Figure 12.13 for its thermal characteristics.) Ambient temperature com-... 

In this case the relay is in the form of a bridge circuit and thermal detection is achieved through various methods other than a bi-metallic heater element discussed below. 

No industrial poisoning by Bi metal has ever been reported but ingestion of compounds and inhalation of dust should be avoided... 

Dry bulb sensors may be bi-metal strips, thermistors or refrigerant-filled phials or bellows responding to pressure differences caused by temperature change. These, in turn, provide an electrical or mechanical signal. The mechanical items are used to alter the value of potentiometers or make-or-break contacts. The signals are transmitted to amplifiers, which respond to the degree of error. An important feature is the proportional band of temperature over which the controls call for up to full plant capacity. 

Corrosion and its Prevention at Bi-Metallic Contacts, Admiralty and Ministry of Supply Inter-Service Metallurgical Research Council, HMSO, London (1956)... 

Some of these bi-metallic oxyalkoxides are able to polymerize oxiranes to high-molecular weight poly-ethers8 b) (M.W. of the order of 106 ). The resulting polymers reveal a quasi-living character, their DPn increases with conversion and is further... 

In their pioneering work on the formation of photoelectrochemically active metal sulfides by oxidation of the parent metal electrode. Miller and Heller [29] reported the anodic formation of polycrystalline Bi2S3 on a bismuth metal electrode in a sodium polysulfide cell, wherein this electrode was used in situ as photoanode. When a Bi metal electrode is anodized in aqueous sulfide solutions a surface film is formed by the reaction... 

Although diphosphine disulfides of formula R2P(S)P(S)R2 take up a trans conformation in the solid state (see Section 5.2.3), upon coordination to a metal centre they can rearrange to adopt a cis conformation, hence facilitating bidentate chelation of the metal (e.g., Equation 78).117 In addition, a cis-bridging mode has also been proposed for these ligands in bi-metallic complexes.117... 

The third class, Class III, contained those mixtures exhibiting the greatest extent of reaction. Included in this class were Sb203, Sb°(metal), Bi°(metal), bismuth trioxide (B i 2 0 3) and antimony trisulfide (Sb2S3). These data are summarized and compared to those from the simple PP/DBDPO mixture in Table VII. 

Figure 7.3. Another projection of the molecular structure of the 1,1 -bi metal lie compound 10 (X — C CPh ...

As representatives of this class of compounds, one hindered and one non-hindered gem-boriozirconocene alkene were prepared [54]. Hydrozirconation of a 1-alkynyldioxaborolane with Cp2Zr(H)Cl in either 1,4-dioxane or THF proceeded readily by a syn addition to give the essentially pure ( )-l,l-bis-metallic boriozirconocene 45 [12]. This bis-metallic complex 45 was also reacted with various electrophiles, thereby generating the alkenylboron derivatives 53—57 as shown in Scheme 7.17. 

Heat detectors are activated by either melting a fusible material, changes in electrical current induced by heat loads on bi-metallic metals, destruction of the device itself by the heat, or by sensing a rate of ambient temperature rise. 

For example, consider the bi-metallic alloy known as bronze, which contains tin (30 mol%) and copper (70 mol%). There are two activities in this alloy system, one each for tin and copper. The activity of each metal is obtained as its respective mole fraction x,... 

A synthetic alternative to this is the chemical reduction of metal salts in the presence of extremely hydrophilic surfactants have yielded isolable nanometal colloids having at least 100 mg of metal per litre of water [105], The wide range of surfactants conveniently used to prepare hydrosols with very good redispersibility properties include amphiphilic betaines A1-A4, cationic, anionic, nonionic and even environmentally benign sugar soaps. Table 3.1 presents the list of hydrophilic stabilizers used for the preparation of nanostructured colloidal metal particles, and Table 3.2 shows the wide variety of transition metal mono- and bi-metallic hydrosols formed by this method [105,120],... 

Using this method, homogeneous alloys, segregated alloys, layered bi-metallics, and decorated particles are all readily accessible. An obvious advantage of the precursor concept over the conventional salt-impregnation method is that both the size and the composition of the colloidal metal precursors may be tailored independent of the support. Further, the metal particle surface may be modified by lipophilic or hydrophilic protective shells and coated by intermediate layers, e.g., of oxide. The modification of the precursor by dopants is also possible. 

Promoter species have been mentioned previously. These are additional metals or organic compounds present in either the original alloy or in the lixiviant. They are more than just a second catalytic metal, although bi-metal skeletal catalysts are possible. Promoter species increase the activity of the... 

The first known Bi cations [43] were synthesized in acidic NaAlCl4/AlCl3 melts by reaction of Bi metal and BiCl3 with AICI3 as the chloride acceptor or by direct fusion of Bi metal and BiCl3 as shown in Eqs. 1-3 ... 

Only recently [42a, 46, 47] it was found that the presence of an electron rich transition metal such as Ir in melts of BiX3 (X = Cl, Br) and Bi metal leads to the formation of large isolated and weakly coordinating cluster anions of type [IrBi Xn]-and [IrBi Xn]2- that stabilize the smaller hitherto unknown Bis+ and Bi 2+ in the interstices of the anion lattice (Eq. 5). 

Leger, J.M., Preparation and activity of mono- or bi-metallic nanoparticles for electrocatalytic reactions. Electrochimica Acta, 2005. 50(15) p. 3123-3129. 

There is considerable interest in extending PEFC technology to the direct methanol and formaldehyde electro-oxidation (34, 35). This requires Pt-based bi-metallic catalysts. Tests have been conducted with gas diffusion type Vulcan XC-72/Toray support electrodes with Pt/Sn (0.5 mg/cm, 8% Sn) and Pt/Ru (0.5 mg/cm, 50% Ru). The electrodes have Teflon content of 20% in the catalyst layer. 

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