The phrase "as a protective coating" is correct and usable in written English.
It can be used when describing a layer or substance applied to a surface to prevent damage or deterioration.
Example: "The metal was treated with a special paint as a protective coating to prevent rusting."
Alternatives: "as a shielding layer" or "as a safeguarding cover".
To serve as a protective coating when applied in high-temperature conditions with an appropriate nanohardness, such as coatings on glass molding dies, the coating must endure an annealing treatment in an oxygen-containing atmosphere at 600 °C.
Particularly, as-fabricated CoCrAlYTaCSiAl2O3 coating exhibits much better wear resistance than CoCrAlYTaCSi coating and other MCrAlY/oxide metal-matrix coatings prepared by HVOF or other technologies, showing promising potential as a protective coating of Ni-alloy based hot parts.
Black varnish is widely used as a protective coating for interior and exterior ironwork such as pipework, tanks, stoves, roofing, and marine accessories.
In the 6th century ad, another Greek physician, Aëtius, mentioned that certain nut oils could be used as a protective coating.
Weathering steel — often known by its old brand name, Cor-Ten — develops a fine layer of rust, which then acts as a protective coating against moisture, slowing its own corrosion process almost to a stop.
A tough, transparent plastic resistant to attack by chemicals or by weathering, it is commonly manufactured in the form of a film and applied as a protective coating for outdoor surfaces such as building siding or solar collectors.
It serves as a protective coat to the gastric mucosa maintaining a stable pH and minimizing direct enzymatic attack by pepsin.
Jewelry with lead is not a danger, Guo LiSheng, a deputy director general at China's General Administration for Quality Supervision, Inspection and Quarantine, wrote in a March letter to the commission, as long as it is covered by a protective coating.
Many new pieces of leather furniture are sold as "finished leather," which means a protective coating has been applied to the upholstery.
Mitigation measures have constrained operational limits in combination with modifying the manufacturing process of the cladding, such as adding a composite layer or a protective coating to the inner surface of the cladding.
But overall they are about as useful as offering a hedgehog a protective coat of spikes – it promises nothing that patients do not already have.
