Products of Plasma Spray Process

Plasma spray is the process along which Metal, Ceramic and Polymer Powders are heated to the melting or re-crystallization temperature and sprayed with a high velocity onto work piece. Semi molten powder particles deposits on object surface forming a scabby layer. The main advantage of Plasma Spray Process is the wide range of implementable coat materials. As a matter of fact all materials with non-destructive melting behavior can be used as feeding powder in this method. The other advantage is coating feasibility without heating the work piece.
Plasma spray is the process along which Metal, Ceramic and Polymer Powders are heated to the melting or re-crystallization temperature and sprayed with a high velocity onto work piece. Semi molten powder particles deposits on object surface forming a scabby layer. The main advantage of Plasma Spray Process is the wide range of implementable coat materials. As a matter of fact all materials with non-destructive melting behavior can be used as feeding powder in this method. The other advantage is coating feasibility without heating the work piece.
A density of deposit layer of 80% to 95% of nominal value can be achieved. The thickness of coating layer is about 0.2-0.3 mm but thicker layer is obtainable also. For adequate adhesion, Surface Pretreation is required. Germs like oil, grease, rust, paint and other pollutions should be removed completely along surface preparation methods, before coating process.

Feeding Powder in Plasma Spray Method:

One of the other advantages of this method is the vast variety of feeding powders; depend on subjected physical and mechanical specifications. Some 200 type of powders are utilized in this method, categorized as follows: Pure metals, Alloys, Ceramics, Carbides, Especial Composites, inter-metallic compounds. 


Brief introduction and Schematic Structure of Machine:

Figure 1 illustrates the Plasma Spray Gun.
A gas (mostly Argon and sometimes Nitrogen, Hydrogen or Helium) streams between a Tungsten Cathode and water-cooled Anode made of copper. The high frequency discharges generates an electrical arc and continues with a DC Power current. Electrical Arc ionizes the gas to form a plasma jet, raise the gas temperature and expansion increases the pressure and velocity of jet on the nozzle. Powder particles are added to gas vapor at nozzle. Size and shape of particles has a defining role in temperature and velocity of the flow and eventually the quality final coat. The velocity of the jet is 300 to 550 m/s in this method.


System Specification:

- Ability of processing long pieces up to 350 cm with 25-320mm of diameter; attachments can increase performed length to 1200mm and diameter up to 1500mm.
- Plain pieces with maximum dimensions of 2200mm(L) X 460mm(W) X 350mm(T)
- Deposit thickness from 0.02 mm to 3mm
- Ability of spraying interior surface of cylinders with maximum length of 750mm.
- Usable for geometric and non-geometric shapes
- Cutting ability of various types of hard metals and ceramics with maximum thickness of 130 mm, and 100 mm for non-ferrous metals.