High-temperature stabilization

Samarium has a bright silver luster and is reasonably stable in air. Three crystal modifications of the metal exist, with transformations at 734 and 922oC. The metal ignites in air at about ISOoC. The sulfide has excellent high-temperature stability and good thermoelectric efficiencies up to llOOoC. 

Chemical Reactivity - Reactivity with Water No reaction Reactivity with Common Materials Corrosive to most metals. Reactions are slow but accelerated at high temperatures Stability During Transport Stable Neutralizing Agents for Acids and Caustics Not pertinent Polymerization Not pertinent Inhibitor of Polymerization Not pertinent. 

Fluorinated polymers stand out sharply against other construction materials for their excellent corrosion resistance and high-temperature stability. In this respect they are not only superior to other plastics but also to platinum, gold, glass, enamel and special alloys. The fluorinated plastics used in process plants are polytetrafluorethylene (PTFE), fluorinated ethylene/ propylene (FEP), polytrifiuoromonochlorethylene (PTFCE) and polyvinyl fluoride (PVF). They are much more expensive than other polymers and so are only economical in special situations [59]. 

At present, high-temperature stabilization of polyolefins is still misunderstood besides, this problem presents serious difficulties. Stabilization of thermal oxidation and photoinduced destruction with the use of stabilizers in this case is inefficient, since at high temperatures these stabilizers are easily evaporated out of the polyolefin melt and decomposed with the formation of radicals capable of initiating additional kinetic chains of destruction. 

In general, properties of polyether sulfones are similar to those of polycarbonates, but they can be used at higher temperatures. Figure 12-6 shows the maximum use temperature for several thermoplastics. Aromatic polyether sulfones can be extruded into thin films and foil and injection molded into various objects that need high-temperature stability. 

The borides listed above can all be produced by CVD. With a few exceptions, they have found only limited industrial applications so far, in spite of their excellent properties of hardness, erosion resistance, and high-temperature stability. 

O2, and hydrocarbons, leading to a NH3 selective sensor. Arguments in favor of using a zeolite-based sensor in NH3 detection for automotive apphcations are low cost, high temperature stability, and suitability for use in thick-film technology, of common use in the automotive industry [72]. The sensors were tested on an engine test bank and the authors claim that the sensor itself meets aU the technological and economical demands of the automotive industry [73]. 

The phase transition boundaries (phase envelope) of adamantane need to be investigated and constmcted. Predictable and diverse geometries are important features for molecular self-assembly and pharmacophore-based dmg design. Incorporation of higher diamondoids in solid-state systems and polymers should provide high-temperature stability, a property already found in polymers synthesized from lower diamondoids. 

Figure 3.60. Quats with high temperature stability a) 4-dialkylaminopyridinium chloride b) bis [tris(dimethylamino)phosphine]iminium chloride.

Casanova, M., Rocchini, E., Trovarelli, A., et al. (2006) High-Temperature Stability ol V205/Ti02—W03—Si02 Catalysts Modified with Rare-Earths, J. Alloys Comp., 408-412 1108. 

The high-temperature stability of SiC-based ceramics is well-known, and therefore its composite materials have been investigated for application to high-tem-perature structural materials [19-21]. However, well-known SiC-based fibers and matrix-materials stained with alkali salt are easily oxidized at high temperatures in air [22]. This would be a serious problem when these materials are used near the ocean or in a combustion gas containing alkali elements. In particular, a silicon carbide fiber containing boron (a well-known sintering aid for SiC) over 1 wt% was extensively oxidized under the above condition. In this... 

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