electroplating coating bronze juntor
Metal coating process wherein a thin metallic coat is deposited on the workpiece by means of an ionized electrolytic solution. The workpiece (cathode) and the metallizing source materialthat (anode) are submerged in the solution where a direct electrical current causes the metallic ions to migrate from the source material to the workpiece. The workpiece and source metal are suspended in the ionised electrolytic solution by insulated rods. Thorough surface cleaning precedes the plating operation. This is the process to electroplating coating bronze juntor.
Plating is carried out for many reasons: corrosion resistance, improved appearance, wear resistance, higher electrical conductivity, better electrical contact, greater surface smoothness and better light reflectance.
Coating thickness 1 – 125 (m
Coating rate 1e-3 – 83000e-3 (m/s
Component area restricted
Curved surface coverage Average
Processing temperature 10 – 77 °C
Surface hardness 25 – 1000 HV
Surface roughness (A=v. smooth) A
Function of Treatment
Corrosion protection (aqueous)
Relative tooling cost low
Relative capital cost high
Plating for aesthetic purposes has its origins in the silver and gold plating of tableware and cutlery (‘Sheffield Plate’), and in chrome and nickel plating for shiny, durable surfaces. Most polymers can now be plated, but care must be taken to prevent the coating breaking or peeling in use. The ability to plate convoluted shapes depends on what is called the ‘surface coverage’ of the plating bath. Some have very poor surface coverage, meaning that only flat or gently curved surfaces can be plated; others – often assisted by mysterious, proprietary additives to the plating bath – can plate complex shapes with re-entrant features.
The equipment cost for electroplating is relatively high, but tooling costs are low. For thin deposits, particularly on small components or areas, large batch processing can make this a very competitive technique.
Almost any metal can be electroplated. Polymers (ABS, PEC ABS/polycarbonate, polyphenylene oxide, polysulfone, polypropylene, nylon, polyester, polyacetal, polystyrene, polycarbonate, epoxy/glass) and other non-electrically conductive materials must be first coated with an electrically conductive material. Cleaning and surface preparation are essential. The usual range of coating thickness is 1 to 50 microns, though thicknesses up to 1mm are routine. Thicker coatings can generally be produced more cheaply or conveniently by other processes: thermal spraying, hot dipping or cladding. The processing temperature is in the range 5 – 80oC.
Coatability – the ease with which an electro-plating can be applied – increases in this order: aluminum, mild steel, brass, copper. Many electro-platings have internal stresses; these can be reduced by heat treatment.
A flavor for the immense range of applications of electroplating, technical and aesthetic, can be tasted by scanning the following list.
Aluminum: electro-plating can substitute for hot dipped aluminum, but is infrequently used.
Brass: lamps and trays, low cost trim, interior automotive hardware, tubular furniture, household
goods, toys, casket hardware, novelties, promote adhesion of rubber to steel.
Bronze: inexpensive jewellery, door plates, hardware, trophies, handbag frames, undercoat for nickel and chromium, bearing surfaces, tableware, household fixtures. It is electroplating coating bronze juntor watch.
Cobalt: alloy electroplates, mirrors, reflectors, applications where high hardness is required.
Co-Ni: magnetic recording, permanent magnet coating on memory drums in digital computers, electro-forming.
Copper: undercoat (improved adhesion, prevention of hydroge embrittlement), wire coatings, stop-off coatings during heat treatment and chemical milling, lubricant during drawing, thermally
conductive coatings on cooking utensils, electro-forming.
Gold: pen points, jewellery, watch and vanity cases, musical instruments, reflectors, name-plates, eyeglass frames, bracelets, trophies, novelties, electrical contacts, springs, electronic parts, laboratory apparatus.
Nickel: heavy base for thin chromium electroplates, trim for automobiles, appliances, business machines and consumer goods, electro-forming, build-up worn and mis-machined parts.
Rhodium: resistant finish for costume jewellery, insignia, emblems, musical instruments, medical and surgical parts, laboratory equipment and optical goods, electrical contacts, reflectors and mirrors.
Silver: tableware, candlesticks, cigarette lighters and musical instruments, bearings, surgical instruments, chemical equipment, electrical contacts.
Tin: food and beverage containers, refrigerator evaporators, food and dairy equipment, hardware, appliance and electronic parts, copper wire, bearings.
Tin-Nickel: cooking utensils, analytical weights, surgical instruments, watch parts, chemical pumps, valves and flow control devices, resistance to marine corrosion.
Tin-Zinc: radio and television parts, cable connectors, relay assemblies, galvanic protection of steel parts contacting aluminum.
Zinc: appliances and automotive parts, finishing small parts (pipe couplings, bolts, nuts, rivets, washers, nails, hinges, hangers, hooks), electrical conduit pipes, silo and tie rods, screening, telephone exchange equipment.
Many electro-plating baths, as electroplating coating bronze juntor process, pose environmental and health hazards. Som contain disagreeable chemicals – those with cyanogens are just nasty. Protection from chemical pollutants and toxic vapor requires special precautions, as does the disposal of the plating medium. Cadmium is toxic, and now banded as plating in many European countries. Alternatives to chromium plating, one of the more unpleasant of processes, are sought but not yet found. Nickel can cause allergies and should be kept away from skin contact. Such gloomy news is not, however, universal: tin, for instance, is non-toxic.
Source CES EDUpack