The aim of this experiment is to determine the best conditions for spraying WC-Co layers on steel plates (JIS SKD 11) by a Low Pressure Plasma Spray (LPPS).
It is found that an appropriate amount of spraying heat at which the compact layers will be coated but the WC in the layers will not be decomposed, is necessary to coat the steel plates with good quality WC-Co layers.
The obtained spraying parameters to satisfy the necessary conditions mentioned above are chamber pressure of 6.7×10³ Pa, spray current of 500A, spray distance of 400mm, Ar gas flow rate of 50L/min and H₂ gas 10L/min. A wear test is carried on samples sprayed under the obtained parameters and compared with untreated steel plate, hard Cr coating, and TD treatment. The wear resistance of the sprayed steel plate is much better than that of the untreated steel plate, and it is found to be superior to hard Cr coating and equivarent to TD treatment in a test of long distance wear.