Zirconium depth profile

An epoxy infiltration process has been used to fabricate zirconium phosphate with much improved physical and mechanical properties for robust applications in various electrochemical devices. Results show that phase composition, microstructure and properties vary gradually along the depth profile, confirming the functionally-graded character of these materials. 

Figure 6 Depth profiles of (A) zirconium, (B) hafnium, and (C) the Zr/Hf atom ratio, in the North Pacific (solid symbols 50°N 145°W McKelvey and Orians, 1998) and in the North Atlantic (open symbols 48°N 15°W Godfrey et a ., 1996).

The surface compositional profile of Figure 6 confirms this interpretation. Sodium, calcium, and barium are depleted from the enamel surface to a depth of 0.4yU.m. Even zirconium is lost from the surface layer. The Si02 network shows little change with milling which indicates that the surface has developed a predominately Si02-rich film during corrosion. 

The biological pump influences, to varying degrees, the distribution of many elements in seawater besides carbon, nitrogen, phosphorus, and silicon. Barium, cadmium, germanium, zinc, nickel, iron, selenium, yttrium, and many of the REEs show depth distributions that very closely resemble profiles of the major nutrients. Additionally, beryllium, scandium, titanium, copper, zirconium, and radium have profiles where concentrations increase with depth, although the correspondence of these profiles with nutrient profiles is not as tight (Nozaki, 1997). 

The preparation of nanocomposite membranes by intra-membrane growth within a proton exchange membrane was first described by Mauritz et al. [45-47]. The then novelty of this approach and the breadth and depth of these studies warrant the following discussion of the results, which in many ways laid the foundation for future work in this area. This group made use of the hydrophilic ionic cluster regions of Nafion for confined, sulfonic acid group catalysed, hydrolysis/condensation reactions of impregnated alkoxides. Nafion membranes were first swollen in ethanol/water, then tetraethoxy-silane (or aluminium, titanium and zirconium alkoxides) permeated from one side of the membrane. In addition to the concentration profile of in-... 

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