Problem solving coatings

But they all oxidise very rapidly indeed (see Table 21.2), and are utterly useless without coatings. The problem with coated refractory metals is, that if a break occurs in the coating (e.g. by thermal fatigue, or erosion by dust particles, etc.), catastrophic oxidation of the underlying metal will take place, leading to rapid failure. The unsafeness of this situation is a major problem that has to be solved before we can use these on-other-counts potentially excellent materials. 

The characteristics of the coatings Industry are such that most companies market many lines of products and within each line there are many individual products, each containing different ingredients. Usually the revenue from each product or each product line can not justify using this modeling/simulation approach in problem solving, because of the extent of technical efforts required. To be cost effective in our industry, only problems which cut across product lines justify the use of this approach. The two examples discussed here are selected to illustrate the types of problems which are amenable to this approach and the advantages and weaknesses of this approach in R. D. work. 

Environmental friendliness is needed not only for products, but also for processes. Hazardous materials used or produced in the production process should be transformed into harmless substances or retained in a closed system (Fig. 1). The latter is a topic and problem-solving issue for wastewater treatment. The latter is composed of many different processes. Several of them are physical vapor deposi-ti(Mi (PVD) and chemical vapor deposition (CVD). Both are called dry coating processes. In this chapter, the dry processes such as PVD and CVD will be introduced and explained as enviromnentally friendly coating processes. 

Colton WC (ed.) (1992) Analysis of Paints and Related Materials Current Techniques for Solving Coating Problems. West Conshohocken ASTM International. 

Swift [237] has discussed the fundamental principles of XPS (and SIMS) and demonstrates the use of these surface analytical techniques in problem solving. XPS can supply information on factors such as surface coating integrity (e.g., in medical polymer applications or plastic coating of metals or wire), contamination, molecular diffusion and adsorption phenomena [238], and characterisation of polymer surfaces. Often XPS is used in conjunction with SIMS to solve problems, as discussed in Section 3.11.1. 

Coriell et al. [92] solved the transient one-dimensional heat and solute diffusion equation without considering convective effect. The situation considered was similar to a diffusion-controlled problem of Coates and Kirkaldy [93] and Maugis et al. [90], which has multiple similarity solutions. Assuming local equilibrium at the solid/metal interface Coriell et al. [92] obtained the equation for the parabolic growth rate which was solved numerically. Using a lead-tin alloy as an example to examine phase stability, it was found that the diffusion path begins at the composition and temperature of one phase, crosses the two-phase region between the liquidus and solidus lines, and terminates at the composition and temperature of the other phase. 

This analysis is far from exact since it assumes a remote groundbed, uniform soil resistivity and uniform defect density in the coating. At best it demonstrates that attenuation is likely to follow an exponential decay and that it will be less severe for larger diameter pipes than for smaller. The problem is more difficult to solve for more complex structures (e.g. congested pipeline networks) and especially so for marine installations where the development of the calcareous deposit introduces the possibility of temporal variations in attenuation. 

In November 1997, Ferrari (France) invited Solvay to help them to solve a problem of recycling PVC coated textile for light mobile structures, especially ones used for shortterm applications (advertising). The Vinyloop is aphysical recycling process making use of an organic solvent to separate the PVC compound from the other materials in a PVC composite. It is a closed loop process the solvent is completely recycled. Aspects outlined include history and a description of the process, precipitated PVC compound evaluation and financial data... 

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