ABSTRACT
Chemical species, other than those constituting the body composition sought, may be added purposely or occur as inadvertent or unavoidable constituents, which may affect densification, as well as resultant properties, positively or negatively. The focus here is on constituents that are intentionally added since their presence or the nature of that presence give some advantage to the resultant body; or more commonly, give some advantageous trade-off in properties, fabricability, costs, or combinations of these. There are also some cases where inadvertent species, not at first identified, are subsequently identified and studied by intentional addition.
