Why is molybdenum and nickel aluminide chosen as bond coat for twin wire spray metallising

We are interested to know why bond coating of molybdenum wire or nickel aluminium wire is used as bond coat in the twin wire spray process.Since these wires are very expensive, we will like to know if any cheaper wire can be replaced keeping in view the cost consideration.Since SS 310 is used as bonding material for welding of unknown steel by manual arc welding process,can this be used in twin wire arc spray as a bond coat.

They were chosen because they work better than anything else that they tried. It is mandated by specifications for a lot of dual wire spray as well as flame and plasma spray.

If you are trying to save money, try to cut down the overspray. One possibility is a smaller rig and smaller wire yielding a smaller spray pattern. Where I worked, overspray was probably equal to the amount that ended up on the part.

The last thing that you want is a rework. Now that is expensive.