AbstractDilution of a hardfacing alloy by the substrate can cause significant reductions in the hardness and wear resistance of the deposited coating. Application of a second layer of hardfacing alloy is one of many techniques used to minimise dilution. However, research into the hardfacing of grey cast iron by spraying and welding processes to resist abrasive wear has shown that, in general, no benefit is derived from the application of two layers rather than one layer of alloy: application of the second layer therefore appears to be economically unwarranted.