Substrate materials real surfaces

The energy densities of laser beams which are conventionally used in the production of thin films is about 10 — 10 Jcm s and a typical subsU ate in the semiconductor industry is a material having a low drermal conductivity, and drerefore dre radiation which is absorbed by dre substrate is retained near to dre surface. Table 2.8 shows dre relevant physical properties of some typical substrate materials, which can be used in dre solution of Fourier s equation given above as a first approximation to dre real situation. 

The electrochemical active surface area (EASA) of fuel cell Pt-based catalysts could be measured by the electrochemical hydrogen adsorption/desorption method. For carbon supported Pt, Pt alloy, and other noble metals catalysts, the real surface area can be measured by the cyclic voltammetry method [55-59], which is based on the formation of a hydrogen monolayer electrochemically adsorbed on the catalyst s surface. Generally, the electrode for measurement is prepared by dropping catalyst ink on the surface of smooth platinum or glassy carbon substrate (e.g, a glassy carbon disk electrode or platinum disk electrode), followed by drying to form a catalyst film on the substrate. The catalyst ink is composed of catalyst powder, adhesive material (e.g., Nafion solution), and solvent. 

It seemed appropriate, given the ultimate biological focus of our previous survey study [1], to employ air-exposed surfaces, at least initially. For example, typical model physical-chemical studies of protein adsorption on metal surfaces are carried out on air exposed surfaces [2]. Our array of substrate materials were chosen both for their desirable spectroscopic characteristics as well as their real or potential biophysical applications [1]. 

Chapter 2 discusses the real surface (substrate) on which the film must be deposited. The real surface never has the same composition as the bulk material. With some materials, such as polymers, the surface and bulk material are affected by its history. 

The nature of the real surface depends on its formation, handling, and storage history. In order to have reproducible film properties, the substrate surface must be reproducible. This reproducibility is attained by careful specification of the substrate material, incoming inspection procedures, surface preparation, and appropriate handling and storage of the material. 

In Ch. 2 the nature of real surfaces and the associated substrate material were discussed. In order to have good adhesion it is important that the substrate surface and near-surface... 

Real-time monitoring of deposition or dissolution from liquids can be performed using TSM, APM, or FPW devices. For example, Kanazawa and Doss [179] demonstrated the use of TSM devices as real-time rate monitors of electroless nickel deposition, while Ricco and Martin [180] demonstrated a similar use of APM devices for electroless deposition of copper directly onto the quartz substrate. TSM devices have also been used to monitor surface accumulation of thermal degradation products from jet fuels [181]. The ability to rapidly quantify the rate of accumulation can be used in designing jet fuels with improved thermal stability [182,183]. Turning to material removal, monitoring the dissolution of metals in aqueous environments has also been demonstrated [184]. In addition, by intentionally contaminating a TSM with a surface layer similar to the anticipated contamination on a component to be cleaned, a real-time moni-... 

In many cases the surface of the anode is oxidized to lead oxide, which thus is the real anode material. Titanium anodes coated with lead oxide have been found to have a long lifetime [154,155]. In some cases the lead dioxide, a strong oxidant in acid solution, reacts chemically with the substrate [156] and is continuously regenerated whereas it acts as an inert electrode in other oxidations. A review of the basic electrochemistry of Pb02, mainly in relation to the lead battery, has been published [157]. 

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