Table 10.

S/N response for hardness of the coatings.

Parameter	Mean S/N Ratio
	Level 1	Level 2	Level 3	ΔM
A	53.48	53.10	50.91	2.57
B	52.04	52.64	52.81	0.77
C	52.67	52.51	52.31	0.36
D	52.31	52.71	52.47	0.40