Sheradizing.
Sherardizing is a diffusion process in which articles are heated in the presence of zinc dust. The process is normally carried out in a slowly rotating closed container at temperatures ranging from 320-500°C.
The resultant zinc/iron alloyed coating is subsequently zinc phosphated or chromated, resulting in a clean, passivated, matt grey surface. The coating closely follows the contours of the base material and uniform coatings are produced on articles, including those of intricate shapes. Carbon steels, low alloy steels, sintered steels, malleable grey iron and cast iron are suitable for sherardizing. The process does not give rise to hydrogen embrittlement.
Main Benefits.
Chrome VI Free alternative
Long term corrosion protection
Coating thickness range available 15-80μm
Salt spray resistance sherardizing - 96 hours
Sherardizing 1000 - 3000 hours
Damages resistance
Uniform Coating
Excellent base for topcoats
Additional Treatment.
In addition to the standard passivated sherardized surface, stains, paints, special lubricants, sealants or organic coatings (duplex) may be applied to enhance the corrosion resistance and/or decorative appearance or to regulate the coefficient of friction. A further enhancement of the coating offers in excess of 500 hours of salt spray resistance.
Properties.
Long term sacrificial environmental protection.
Uniform diffused zinc/iron alloy coating.
Protection of irregularly shaped and recessed components.
A relatively high degree of wear and abrasion resistance.
No hydrogen embrittlement.
Matt grey textured surface, suitable for the application of paint systems.
Sacrificial.
Relatively low processing temperature.
Dry process suitable for sintered material.
Typical Properties.
Cable hooks for supporting signalling and telecommunication cables along the walls of the Transit Railway in Hong Kong.
Metal fittings and fasteners used in the construction of segmented tunnel linings for London ring main, Jubilee underground line & Channel Tunnel.
Rubber bonding, anti-roll bar link, Ford Motor Company
Mining Industry, roof support hinge pins.
Submarine telecommunications systems, bend limiters, universal joints.
Rail track fittings.