There are many vital industrial and
engineering applications for electro-deposited hard chromium.
The characteristics which
make hard chrome plating a practical and necessary application in its many uses are
hardness, low coefficient of friction, chemical inertness, resistance to wear and
corrosion, and an inherent micro crack pattern for the retention of lubricants.
Chromium is delivered to a
plating facility in flake form in one hundred pound containers. These reddish brown flakes
are combined with water at a concentration of thirty ounces per gallon of water.
This solution alone will not plate onto a metal substrate without the addition of sulfuric
acid as a catalyst at a ratio of 100/1 chromic acid to sulfuric acid. By using this
properly balanced solution containing these three constituents and operating at a
temperature of approximately 130 degrees Fahrenheit, a plater utilizes direct current from
an electrical rectifier and plates at a rate of one-half to one thousandths thickness per
hour onto a surface.
In this newsletter, we have
covered only one hard chrome plating solution in our explanation. This solution type
"Standard Chromic Acid/Sulfate" is used most commonly in industry today.
There are many variables in
the "art" of hard chrome plating which will be covered in subsequent
newsletters. We hope the presentation of this information is interesting to you and helps
answer questions you may have.
With this newsletter, we plan
to cover the following subjects in the coming months: