MODIFIED ZINC POWDER FOR THERMO-DIFFUSION ZINCING, PROCEDURE FOR APPLICATION OF COATING AND CLUTCH WITH THERMO-DIFFUSION ZINC COATING Russian patent published in 2010 - IPC B22F1/02 C23C10/36 E21B17/02 

FIELD: metallurgy.

SUBSTANCE: modified zinc powder with specific surface not less, than 0.8 m²/g with zinc contents up to 99 % has surface film of active zinc oxide on particles of zinc of 10-60 mcm dimension. Surface film of active zinc oxide has fine grain dendrite-flaky structure and thickness not less, than two microns. The procedure for application of thermo-diffusion zinc coating on metallic items consists in performing chemical-thermal treatment of items in a rotating retort in a suspended layer of modified zinc powder at reverse motion of the retort with a period of 2-4 minutes between change of rotation direction at frequency of retort rotation 2-3.5 rev/min. A clutch is subject to zincing; the clutch is made with threaded surface and has thermo-diffusion coating of not less, than 20 mcm thickness. Thickness of coating is 31-60 mcm; deviation from average value of thickness coating on threaded surface is not more, than 20 %.

EFFECT: producing coating with upgraded operational properties due to increased uniformity of coating thickness and upgraded fracture resistance.

3 cl, 2 tbl, 5 ex