Agglomerates mechanical strength

These incorporate membranes fabricated from insoluble crystalline materials. They can be in the form of a single crystal, a compressed disc of micro-crystalline material or an agglomerate of micro-crystals embedded in a silicone rubber or paraffin matrix which is moulded in the form of a thin disc. The materials used are highly insoluble salts such as lanthanum fluoride, barium sulphate, silver halides and metal sulphides. These types of membrane show a selective and Nemstian response to solutions containing either the cation or the anion of the salt used. Factors to be considered in the fabrication of a suitable membrane include solubility, mechanical strength, conductivity and resistance to abrasion or corrosion. 

The PBXs are powdered explosives to which plastic binders have been added. The binder is usually precipitated out of solution in the preparation process such that it coats the explosive crystals. Agglomerates of these coated crystals form pressing beads. The beads are then either die pressed or isostatically pressed at temperatures as high as 120°C. Pressures from 1 to 20 kpsi then produce pellets, or billets, with densities as high as 97% of the theoretical maximum density (TMD). The billets thus produced have good mechanical strength and can be machined to very close tolerances. Table 4.3 lists various PBXs in common use in the U.S. Department of Energy s (DOE) weapons laboratories. Table... 

For high filled products the main criteria for quality is the distribution of the solids in the binder. Only when agglomerates are broken up and the solids are wetted evenly with the binder the desired product properties such as mechanical strength or morphology can be achieved. 

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