Moisture resistant layered sleeve heater and method of manufacture thereof

A method of forming a layered heater assembly comprising:

• forming a plurality of layers onto a substrate, the plurality of layers including a resistive element layer;
• forming electrical terminations in contact with the resistive element layer;
• securing a protective cover over the layers using a laser welding process, wherein edges of the protective cover are welded circumferentially around raised end portions of the substrate and welded longitudinally along a slotted portion of the substrate;
• securing a pair of lead wires to the electrical terminations;
• and
• securing a lead cap assembly around the pair of lead wires and to the protective cover using a laser welding process.

A method of forming a heater assembly comprising:

• preparing a substrate having an outer surface and a recessed area recessed from the outer surface;
• thermally spraying a resistive layer on the outer surface of the substrate;
• forming a pair of terminal pads in the recessed area and connecting the terminal pads to the resistive layer;
• and
• securing a protective layer to the substrate to protect the resistive layer and the terminal pads against moisture intrusion.