Pulsed Electrode Surfacing

• Pulsed electrode surfacing is a technique whereby monolithic or multiple metallic or even ceramic thin layers can be deposited onto metals. 

• The Process entails the rapid cyclic D.C. capacitance discharge to an electrode materials, which results in the transference of electrode material to the surface of the work piece. 

• The apparatus necessary for this method of surface treatment is portable, can be operated in air and requires little operator training.

Advantages

• Metallurgical bond

• Low heat input eliminates distortion or metallurgical  changes in substrate

• Special properties and amorphous layers possible through rapid solidification

• Coatings typically exhibit higher load tolerance, lower wear rates and lower corrosion rate than similar materials applied by other processes.

• Little or no substrate preparation required

• Reproducible process

• Operations easily trained

• Portable process and equipment

• Easily automated

• Applicable to i.d. surfaces and complex shapes

• Can apply most electrically conductive materials (metals and cermets)

PES coatings applied to date

Coatings

Substrates

Results of changing to PES coatings

• Mechanically bonded coating replaced by much stronger metallurgical bonded coating

• Friction coefficients reduced by order of magnitude at high contact stresses

• Fabrication lead times reduced by factors of 3 to 10

• Costs reduced by 60%

Advantages of PES over competing processes

• No masking/damasking, which is time consuming and is required on all competing processes except spark deposition

• No toxic/hazardous chemical to use or dispose of as in electro/electroless plating and some CVD processes

• No debonding of the coating when subjected to large strains as in all competing processes except ion implantation, boronizing and spark deposition processes

• No elevated temperature distortion and annealing of the substrate as in spray processes, diffusion alloying and CVD processes

• No expensive (to purchase and maintain) vacuum equipment as in sputtering, PVD, ion plating, ion implantation and plasma processes

• No heat treating or reheat treating to develop properties lost during coating as in CVD, spray processes and diffusion alloying

• Transportable portable equipment unlike all other processes

Applications of PES