Abstract: A method of manufacturing a screen used to block the passage of particulate material in a gas flow path is disclosed. A screen substrate, typically comprising a steel mesh, grate or perforated plate, is coated by thermal spraying to apply a coating comprising a relatively soft metallic base material and a hard phase in the base material. Various feedstock materials for the thermal spraying process are disclosed. Preferably, the coating is applied by providing a number of spray heads, each of which is inclined relative to the plane of the screen at an angle between 15 and 45 degrees, so that a greater than 180 degree coating of each portion of the screen is achieved. The resulting screens have application in exhaust systems of fossil fuel fired plants, upstream of a selective catalytic reduction (SCR) system.