Reactive plate

Each section consists of a reaction plate where the reaction mixture flows, surrounded by two cooling plates containing the UE. The reactants and catalyst are stored separately and put into contact at the opening of the first reaction plate. The pilot holdup is typically 1.5 1. The successive plates of the reactor can be represented as shown in Figure 12.1. Inside the reactive plate (RP), the environment of the reaction mixture is composed of PEEK. The UE flows between two stainless steel plates, the sandwich plate (SP) and the transition plate (TP). 

Fig. 5. Reactive-ion plating using auxiUary electrode for low pressure operation in deposition of compounds (6).

Concurrent bombardment during film growth affects film properties such as the film—substrate adhesion, density, surface area, porosity, surface coverage, residual film stress, index of refraction, and electrical resistivity. In reactive ion plating, the use of concurrent bombardment allows the deposition of stoichiometric, high density films of compounds such as TiN, ZrN, and Zr02 at low substrate temperatures. 

The relative reactivity of thermosetting powders can be easily deterrnined by the gel time or stroke-cure test. A small amount of powder is placed on a hot plate, usually at 200°C, and the time until the coating composition gels, or no longer forms fibers, is deterrnined. Powders are characterized by relative gel times (cure rate) as shown in Figure 1. 

Van Wingerden and Zeeuwen (1983) demonstrated increases in flame speeds of methane, propane, ethylene, and acetylene by deploying an array of cylindrical obstacles between two plates (Table 4.3). They showed that laminar flame speed can be used as a scaling parameter for reactivity. Van Wingerden (1984) further investigated the effect of pipe-rack obstacle arrays between two plates. Ignition of an ethylene-air mixture at one edge of the apparatus resulted in a flame speed of 420 m/s and a maximum pressure of 0.7 bar. 

Adsorbers, distillation colunuis, and packed lowers are more complicated vessels and as a result, the potential exists for more serious hazards. These vessels are subject to tlie same potential haz. uds discussed previously in relation to leaks, corrosion, and stress. However, llicse separation columns contain a wide variety of internals or separation devices. Adsorbers or strippers usually contain packing, packing supports, liquid distributors, hold-down plates, and weirs. Depending on tlie physical and chemical properties of the fluids being passed tlirough tlie tower, potential liazards may result if incompatible materials are used for llie internals. Reactivity with llie metals used may cause undesirable reactions, which may lead to elevated temperatures and pressures and, ullinialely, to vessel rupture. Distillation columns may contain internals such as sieve trays, bubble caps, and valve plates, wliicli are also in conlacl with tlie... 

The relatively low temperature rise of during plating allows the coating of temperature-sensitive materials. Furthermore, composite articles, even those having porous and otherwise reactive surfaces, can be successfully plated. 

Plating is carried out in a closed system whose atmosphere is adjusted to contain the metal-gas and a second gas which may be an inert diluent or a reactive gas (as in 1 above). is heated, for example by high frequency, and this then initiates deposition of M, by one of the above steps. Spent reaction products are exhausted and where possible reclaimed and recycled. 

It is not possible to plate rhodium directly on to reactive metals of the type mentioned above, in view of the acid nature of the electrolyte, but copper and its alloys, e.g. nickel-silver, brass, phosphor-bronze, beryllium-copper, which are of special importance in the electrical contact field, may be plated directly. Even in this case, however, an undercoat is generally desirable. 

It is hard to generalize about the chemical reactivities of a group of elements since reactivities depend upon two factors (A) the relative stability of the specific compounds formed compared with the reactants used up, and, (B) the rate at which the reaction occurs. In special cases there are other complications. For example, chromium metal (familiar in the form of chrome plate) is highly reactive toward oxygen. Still, a highly polished piece of chromium holds... 

These compounds may reduce the reactivity of lithium and make the lithium deposition morphology smoother as a result of the spontaneous electrochemical alloy formation during the charging of lithium on the anode. The lithium was plated on... 

The bed of parallel plates coated with Raney nickel catalyst was much more reactive than the bed of precipitated nickel. This was revealed by the generally lower CO concentration in the product gas during operation with the parallel plate bed for example, after 450 hrs stream time, it was 0.01% with the bed of sprayed Raney nickel (experiment HGR-14) and 0.05% with the bed of precipitated nickel catalyst (experiment HGR-13). 

The higher reactivity of the Raney nickel coated plates is also illustrated by the plots of catalyst temperature vs. bed length (Figure 10). The maximum bed temperature (indicative of near-completion of metha-nation) was consistently reached within a shorter distance from the gas inlet, and the slopes of the curves are correspondingly steeper for the more reactive bed of parallel plates coated with Raney nickel. 

Titanium, Ti, a light, strong metal, is used where these properties are critical— in widely diverse applications such as jet engines and dental fixtures such as partial plates. Although titanium is relatively reactive, unlike scandium it is resistant to corrosion because it is passivated by a protective skin of oxide on its surface. The principal sources of the metal are the ores ilmenite, FeTiO , and rutile, Ti02. 

Reactive ion plating is similar to reactive sputtering and evaporation with applications in optical, wear, abrasion, lubrication, and decorative coatings. 

The chemical reactivity of metallic Mg has been utilized in several ways. It is employed in the reduction step in the manufacture of Ti, in the deoxidation and desulfurization of steels and in the nodularization of cast iron. It has also been used for the preparation of photoengraving plates, in dry batteries, and as a sacrificial anode for cathodic protection of other metals. 

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