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Hard chrome plating. Hard chrome, also known as industrial chrome or engineered chrome, is used to reduce friction, improve durability through abrasion tolerance and wear resistance in general, minimize galling or seizing of parts, expand chemical inertness to include a broader set of conditions (such as oxidation resistance), and bulking ...
Black nickel plating was developed around 1905, and between the two wars, black chrome plating (first German patent 1929.GP 607, 420), which saw wider use only from the mid-1950s. [14] After the First World War, the first procedures for anodic oxidation and coloring of anodically oxidized aluminium were developed (1923, 1924.DRP. 413876).
Plating is a finishing process in which a metal is deposited on a surface. Plating has been done for hundreds of years; it is also critical for modern technology. Plating is used to decorate objects, for corrosion inhibition, to improve solderability, to harden, to improve wearability, to reduce friction, to improve paint adhesion, to alter conductivity, to improve IR reflectivity, for ...
A #7 finish is produced by polishing with a 280–320 grit belt or wheel and sisal buffing with a cut and color compound. This is a semi-bright finish that will still have some polishing lines but they will be very dull. Carbon steel and iron are commonly polished to a #7 finish before chrome plating.
Recent revisions of ASTM B633 defer to ASTM F1941 for zinc plating mechanical fasteners, like bolts, nuts, etc. 2019 is the current revision for ASTM B633 (superseded the revision from 2015), which raised required tensile thresholds when confronting hydrogen embrittlement issues and addressed embrittlement concerns in a new appendix.
The processed surface is then coated with electroless copper or nickel before further plating. This process gives useful (about 1 to 6 kgf /cm or 10 to 60 N /cm or 5 to 35 lbf /in) adhesion force, but is much weaker than actual metal-to-metal adhesion strength.
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4. Acid chrome plating is dependent on a "slime layer" containing Cr(+2) that is critical, formed in the initial start of current. 5. Cr(+3) plating isn't new or difficult and has much better throwing power and adhesion to base metals. Problem is matte finish. Great for corrosion resistant plate of small parts but more common zinc-nickel etc ...