Abstract
In the mechanical plating using Fe-Zn system ejection powder (Z-iron), repeated use results in finer particle size, and to maintain high deposit density on a continuous basis, it is necessary to bleed out the fraction of the powder that has a detrimental effect on plating efficiency.
In this study, the plating densities of various mixtures were evaluated in order to determine effective bleeding methods. The principal results obtained are as follows:
(1) The deposit density obtained by ejecting a fresh mixture of ZZ-48 and ZZ-48H powder is greater than that expected from a simple sum of the deposit densities of ZZ-48 and ZZ-48H.
(2) Ejection of ZZ-48 after ZZ-48H results in a slightly lower deposit density than ejecting ZZ-48H after ZZ-48.
(3) The dust fraction produced during pulverization of ZZ-48H greatly reduces the deposit density of fresh Z-iron.
(4) The presence of magnetics portion of -60 mesh fraction resulting from repeated ejection was detrimental to plating efficiency.
(5) Powder that has detrimental due to ejection can recover its deposit plating efficiency with thermal treatment.
