Thermal deposition

The second form consists of Pt metal but the iridium is present as iridium dioxide. Iridium metal may or may not be present, depending on the baking temperature (14). Titanium dioxide is present in amounts of only a few weight percent. The analysis of these coatings suggests that the platinum metal acts as a binder for the iridium oxide, which in turn acts as the electrocatalyst for chlorine discharge (14). In the case of thermally deposited platinum—iridium metal coatings, these may actually form an intermetallic. Both the electrocatalytic properties and wear rates are expected to differ for these two forms of platinum—iridium-coated anodes. 

The basic operations in dust collection by any device are (1) separation of the gas-borne particles from the gas stream by deposition on a collecting surface (2) retention of the deposit on the surface and (3) removal of the deposit from the surface for recovery or disposal. The separation step requires (1) application of a force that produces a differential motion of a particle relative to the gas and (2) a gas retention time sufficient for the particle to migrate to the coUecting surface. The principal mechanisms of aerosol deposition that are apphed in dust collectors are (1) gravitational deposition, (2) flow-line interception, (3) inertial deposition, (4) diffusional deposition, and (5) electrostatic deposition. Thermal deposition is only a minor factor in practical dust-collectiou equipment because the thermophoretic force is small. Table 17-2 lists these six mechanisms and presents the characteristic... 

The active coating consists of a thermally deposited mixed metal oxide coating, the composition of which is considered proprietary information, although it is known that certain filler materials, e.g. Ta, may be added to the mixed metal oxide to reduce the precious metal content of the coating, and hence the cost of the anode. 

Platinised tantalum Platinised niobium Platinised titanium Platinum Thermally deposited noble metal oxide on titanium High- silicon/ chromium iron... 

Electrostatic Casella thermal Deposition on 1-85 90-100 Microscopy Poor for large particles. Collection... 

Depending on temperature, pressure and geological conditions of deposition, the hydro-thermal deposits maybe classified into five types, the details of which are given in Table 1.9. 

In most photoacoustic experiments, it has been generally assumed that the experimental volume change resulted only from the thermal deposition of energy to the solvent. In such cases, the ratio of the volume change of the sample to that of the reference compound, a, could be related to the enthalpy of reaction... 

Instead of using plasma-polymerized polyfluorocarbon as HIL, Qiu et al. utilized a thermally deposited Teflon (polytetrafluoroethylene) thin layer as a HIL, which results in... 

Figure 9. Temperature programmed oxidation (TPO) data showing CO2 evolution m/e = 44) of thermally deposited carbon from a Cu-Ce02-YSZ SOFC anode material after exposure to n-butane for 30 min (solid line) and a graphite powder sample (dashed line). (Reprinted with permission from ref 172. Copyright 2003 The Electrochemical Society, Inc.)...

Our preliminary cp-AFM results of Au thermal deposition on octanedithiol SAM under UHV condition at room temperature and 10 K revealed short-circuit filament generation. 

Our preliminary AFM observation of Pb thermal deposition on hexadecanedithiol SAM on An/ mica under UHV condition at room temperature revealed continuous penetration of Pb as unpublished results. 

For Au CVD an organogold complex, (trimethylphosphine)methylgold(l) ((Me3P) AuCHs), has been used with the result of selective deposition on —SH and —CH3 terminated SAMs maintained at 70 °C [81-83]. Further, CVD at 70 °C on SAMs with —SH, —CH3, and —OH terminal groups was studied by spectroscopic and microscopic analyses with the result that no penetration was observed for the-SH surface but was observed for the -CH3 and -OH surfaces. Standard thermal deposition of Au on the ASH surface showed, in contrast to CVD, that the penetration cannot be completely prevented [83]. 

No significant differences have been established between heulandite and laumontite in sedimentary formations in the zones of deep epigenesis (initial metamorphism), on the one hand, and the same minerals in hydro-thermal deposits, on the other. Apparently, this will require more factual data. Nevertheless, the distribution of these zeolites and the associations of clay minerals permit a distinction between the zeolite facies of regional epigenesis-metamorphism and the zeolite mineralization in geothermal areas (recent hydrothermal systems). 

The reference ISFET can be modified by chemically reacting the SiOH groups with trimethoxysilanes [7]. An alternative method involves deposition of a hydrophobic polymer on the surface, for example by thermal deposition of parylene [85]. These layers tend to be chemically bound to the SiOH surface, leading to enhanced stability and long lifetimes. Also the layers are very thin, which is essential because of decreased electrical sensitivity as the insulator thickness increases [9]. For ion-blocking layers, a stable attachment has been realized by plasma deposition [86,87]. 

For silicon nitride films made in a cold-wall, pa rail el-pi ate reactor operating at 50 kHz, 200 mTorr, gas flows of SiH4/NH3/N2 = 140/270/800 seem and 500 watts of power, we can compare chemical and physical properties with thermally-deposited silicon nitride. Such a comparison is shown in Table 1.2... 

The ISFET transducer, described in a previous paper (2), is an n-Si, p-well type device with the sensitive gate consisting of a thermally deposited SiC>2 (1000 A) and an APCVD deposited AI2O3 (600 A) layers. The gate area is 20 pm x 500 pm and the overall chip dimensions are 0.75 mm x 3 mm x 0.38 mm. 

A few gas-phase atom-GeH4 elementary reactions have been studied in detail because of their role in the general mechanism of thermal deposition processes. The most widely studied reaction is that involving H atoms and GeH4 for which hydrogen abstraction (equation 43) is considered the only pathway. 

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