A method for manufacturing a coated metal substrate includes the steps of: (1) inserting a substrate with a chromium(III) oxide layer inside a CVD chamber; (2) heating the substrate to a temperature which falls in the range of 400 to 500 degrees Celsius; (3) transporting gaseous nitrogen (N2) and tantalum chloride (TaCl5) into the CVD chamber for at least two cycles; (4) ceasing the transportation of tantalum chloride (TaCl5) while nitrogen continues to flow from the inlet to the outlet; (5) reacting the tantalum chloride and the chromium(III) oxide and creating by-products; and (6) vacuuming the by-product matter from the CVD chamber via the flowing nitrogen gas.