The plating operation involves covering a part of a greater or lesser thickness of 0.5 microns (decorative chromium) 1/10 mm ground (hard chromium). The required qualities to surface layer is not the same as the intended applications are usually two kinds of plating. It provides shiny surfaces polished chromium decorative chromium aims (Perterbilt chrome). It is used for example for the bumper and door handles.
In case of breakage or porosity of protective film, the underlying metal corrodes in a localized manner and very intense (remember, for example, the degradation of many chromium metal parts in cars with a few decade of life). It is essential, accordingly, an adequate thickness of plating, the minimum value of which depends on the metal to be protected, the environmental conditions and by economic factors.
Deposition of chromium may be deposited directly onto workpiece according to its use. For cylinders it is advisable to perform a sub-layer of nickel 20 microns to limit corrosion. You should know that the chromium deposit has a low cathode efficiency (15%) and cathode occurs a release of hydrogen which weakens the steel and reduces resistance to fatigue. Degassing treatment is to return to mechanical characteristics of part.
There are basically three configurations of bathrooms: based electrolyte salts of chloride, based electrolyte salts of sulphate electrolyte mixture of salts of sulphate and chloride. We use insoluble anodes of graphite to avoid the phenomenon of oxidation of chromium to anodes. The plating can performed in various ways: Plating hot, Plating cold, electroplated .
Used in plating process chemicals and wastes are extremely toxic, in most countries, this process is under strict regulation. In industry, chromium is used for reducing friction, increase wear resistance, increased corrosion resistance. This process provides enhanced resistance to gas corrosion of steel (scaling resistance) at temperatures up to 800 degrees C, high resistance to corrosion in environments such as water, sea water and nitric acid.
The argon ions that result from this field are attracted to target, they hit violently, tearing metal atoms M and projecting into environment. These atoms will then condense on the surface of objects placed in front of target. We then obtain "diode sputtering", which is very slow. It takes between 10 minutes and 1 hour to obtain a deposition thickness of order of microns.
By applying a magnetic field in addition to electric field perpendicular, it significantly increases the density of plasma which is formed around the target, the deposition rate can then reach a commercially acceptable value of order of 1 micron / min. Deposits made by PCM are much less cracked and much more compact than those made by electroplating but they are also much softer. The presence within confines of traces of other elements such as oxygen, nitrogen, carbon, can correct this defect and even achieve much higher hardness.
In some cases, chromium is used for repair parts by increasing the mating surface in case of loosening planting. At the present time can used as a "garage" or "cold" alternative to plasma spraying metal parts of similar material. Typical are the following solutions for plating: Hexavalent chromium, whose main ingredient - chromic anhydride. Trivalent chromium, whose main ingredient - chromium sulfate or chromium chloride. Trivalent chromium bath is rarely used because of constraints imposed on the color, brightness and thickness of coating.
In case of breakage or porosity of protective film, the underlying metal corrodes in a localized manner and very intense (remember, for example, the degradation of many chromium metal parts in cars with a few decade of life). It is essential, accordingly, an adequate thickness of plating, the minimum value of which depends on the metal to be protected, the environmental conditions and by economic factors.
Deposition of chromium may be deposited directly onto workpiece according to its use. For cylinders it is advisable to perform a sub-layer of nickel 20 microns to limit corrosion. You should know that the chromium deposit has a low cathode efficiency (15%) and cathode occurs a release of hydrogen which weakens the steel and reduces resistance to fatigue. Degassing treatment is to return to mechanical characteristics of part.
There are basically three configurations of bathrooms: based electrolyte salts of chloride, based electrolyte salts of sulphate electrolyte mixture of salts of sulphate and chloride. We use insoluble anodes of graphite to avoid the phenomenon of oxidation of chromium to anodes. The plating can performed in various ways: Plating hot, Plating cold, electroplated .
Used in plating process chemicals and wastes are extremely toxic, in most countries, this process is under strict regulation. In industry, chromium is used for reducing friction, increase wear resistance, increased corrosion resistance. This process provides enhanced resistance to gas corrosion of steel (scaling resistance) at temperatures up to 800 degrees C, high resistance to corrosion in environments such as water, sea water and nitric acid.
The argon ions that result from this field are attracted to target, they hit violently, tearing metal atoms M and projecting into environment. These atoms will then condense on the surface of objects placed in front of target. We then obtain "diode sputtering", which is very slow. It takes between 10 minutes and 1 hour to obtain a deposition thickness of order of microns.
By applying a magnetic field in addition to electric field perpendicular, it significantly increases the density of plasma which is formed around the target, the deposition rate can then reach a commercially acceptable value of order of 1 micron / min. Deposits made by PCM are much less cracked and much more compact than those made by electroplating but they are also much softer. The presence within confines of traces of other elements such as oxygen, nitrogen, carbon, can correct this defect and even achieve much higher hardness.
In some cases, chromium is used for repair parts by increasing the mating surface in case of loosening planting. At the present time can used as a "garage" or "cold" alternative to plasma spraying metal parts of similar material. Typical are the following solutions for plating: Hexavalent chromium, whose main ingredient - chromic anhydride. Trivalent chromium, whose main ingredient - chromium sulfate or chromium chloride. Trivalent chromium bath is rarely used because of constraints imposed on the color, brightness and thickness of coating.
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