Plasma nitriding

ASPN is a new industrial solution that enjoys all the advantages of DCPN but does not have its inconveniences.

The active screen acts as a radiation heater and as there is no direct glow discharge at the component, there is no overheating happening and any effect caused by the electrical field is eliminated. This enables proper temperature control and uniformity and allows mixing of parts with different dimensions with the same time - which increases the process efficiency [up to 50% more load density]. Even semi bulk loads can be treated uniformly and efficiently which is not possible with the DCPN process.    

Different-size parts can be treated in the same batch. It also offers the possibility of nitrocarburizing and nitriding of stainless steels.

ASPN has the following advantages:

• Simple process control
• Sintered parts can be nitrided
• Possibility of partial nitriding surfaces
• No Ammonia consumption
  • but a mixture of N2 and H2
• Low energy consumption
• Low gas consumption
  • about 200Nl/h : at least 90% lower than for gas nitriding
• No poisonous consumable and waste
  
• Very large range of applications
• Solves most problems of the common plasma nitriding technology (DCPN)
  
  • Prevents hollow cathode effect
  • Prevents arking issues
  • Prevents edge effect
  • Good temperature uniformity
• High development potential

The ASPN technology is covered by the ION₂-cloud® patent exclusively owned by ALD

DCPN is the historical way to nitride with plasma which has the following advantages:

• Sintered parts can be nitrided
• Possibility of partial nitriding surfaces
• No Ammonia consumption
  • but a mixture of N2 and H2
• Low energy consumption
• Low gas consumption
  • about 200Nl/h : at least 90% lower than for gas nitriding
• No poisonous consumable and waste

However, DCPN process also has limitations which are mainly based on the effects resulting from the formation of an electrical field, as:

• "Hollow-cathode"
  • Effect when parts are placed very close together or if they contain deep holes of small diameter, the overall discharge current can increase so much so that local melting takes place, proper loading is an issue
• Arking
  • Arking can produce very high local temperatures and cause localized melting and/or sputtering of material from this point on the surface. This effect could happen by organic degassing in a localized area of a component's surface, by the presence of non-metallic inclusion in the work piece material > a perfect degreasing of the parts is needed
• “Edge" effect
  • Effect with components containing sharp corners or of complex geometries, can cause different nitriding effects and brittleness risk
• Bad temperature control and uniformity
  • Is an issue to treat components with different cross sections and does not allow to run mixed loads with different part sizes and geometries