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What is Plasma Ion Nitriding       

  Plasma ION nitriding is an industrial surface hardening treatment for iron-based materials. It is the most technically superior of all nitriding processes and has many advantages compared to traditional salt bath and gas nitriding.

A plasma nitrided part is usually ready for use directly after treatment requiring no machining, polishing or any other post-nitriding finishing operations. The process is eco-friendly, saves energy and causes little or no distortion.

Steels are the most common materials treated with plasma nitriding. This process permits the close control of the nitrided microstructure, allowing nitriding with or without compound layer (white layer) formation. In addition to enhanced material performance, the lifespan of your parts will increase with much improved strain limits, fatigue strength, wear resistance and corrosion protection.

With a wide range of process control and optimization possibilities, plasma nitriding makes it possible to achieve stringent requirements not capable by gas or salt bath nitriding. Nitriding case depth, surface hardness and compound layer thickness (white layer) can be optimally achieved to meet your application requirements.

How It Works

The parts are placed in a vacuum vessel, convectively heated to the required process temperature in an atmosphere of specialty gases.

High voltage is then applied between the work pieces and the furnace wall. As the process gases begin to activate (ionize), a corona discharge (violet glow) takes place in the treatment chamber. The high voltage reacts with the positive gas ions, which are energized and accelerate in a direction toward the work piece with much energy creating an “ion bombardment” to the surface.

This ion bombardment can create intense heat in the work piece and must be controlled. Thanks to our state of the art MICROPULS® power supply, the heat is precisely controlled via very fast on-off voltage transition times or “pulse ionization”. The controlled ion bombardment reacts with carbon atoms in the work piece forming nitrides. These nitrides eventually channel their way through the material’s grain boundaries, diffusing into the part leaving behind a hard, non-distorted, smooth surface.

Within an individual process, several parameters such as voltage, gas mixture, pulse frequency, temperature, time, etc. are controlled. Unique combinations of these variables can be developed for exotic applications and saved as a custom “recipe”, which can be run again and again with absolute repeatability.

The Plasma Ion process is done in a vacuum vessel at low temperatures (750°-1040°F or 400°-560°C) where high-voltage electrical charge forms plasma, causing nitrogen ions to accelerate and impinge on the metal. When the nitrogen ions bombard the part they heat up metal, clean the surface, and absorb nitrogen into the surface, and can be applied to any ferrous metal.

 

Benefits of Plasma Ion Nitriding

  • Extends part/tool life
  • Selective hardening process
  • Reusable masking (versus coatings or other surface treatments)jgs ion nitriding process
  • Adds performance, fatigue strength and endurance
  • Enhances surface lubricity
  • Reduces erosion
  • Increases liquid material flow in molds and dies
  • Improves corrosion resistance
  • No post-process machining required
  • Improves wear resistance
  • Zero to minimal growth/distortion
  • Precise and versatile
  • Environmentally friendly process (i.e. free of toxic salts, ammonia and any other toxic gases)
  • Phase controllable compound zone (or white layer)
  • Less distortions than gas nitriding because plasma nitriding is performed at a lower temperature and under a vacuum.
  • Higher surface, case, and core hardness than gas nitriding.
  • Excellent wear resistance: the plasma ion nitriding process produces a compound zone that is dense, nonporous, very hard but not brittle, and has a low coefficient of friction.
  • Reproducible results and better control compared to gas nitriding: the process of plasma nitriding is fully automated and computer controlled.
  • Great surface finish: no additional mechanical treatments are necessary.
  • Easy masking: surfaces requiring selective treatment are easily masked with reusable mechanical masking devices that are 100% effective.
  • Excellent hygiene and working conditions: the process is non-toxic and abides by all modern environmental control standards.
  • Low to high alloyed steels and stainless
  • It produces a compact, dense and more "ductile" compound layers than other nitriding processes
  • Improved surface finish and much cleaner surfaces as compared to salt bath and gas nitriding
  • Possibility of re-oxidization (post nitriding corrosion protection).
  • Components and tools with plasma nitrided surface have an enhanced resistance to wear and crack formation, improved frictional, and sliding properties and higher fatigue strength values. 

 

Typical Applications for Plasma Ion Nitriding

  • Dies and punches for metal forming
  • Gears
  • Crank shafts
  • Feed screws
  • Camshafts
  • Guides
  • Cylinders
  • Mandrels
  • Molds for plastics
  • Molds for casting of nonferrous metals and alloys
  • Milling tools
  • Drilling tools

 

 

Plasma ION Nitriding Before After

Enhance Fatigue Strength and Save Money

Due to increased compressive stregnth at the part surface, fatigue strength is improved five to ten times its typical "non-treated" life, dependent on the material and part design. Studies have show fatigue strength is improved without distortion as compared to other surface treatments, saving customers money.

 

low carbon steel new

Improve Corrosion Resistance

Plasma Ion Nitriding case hardening process can create a controlled white layer (compound zone) which will improve a parts susceptibility to corrode or rust. This nitrogen enriched layer helps combat the elements and keep your parts looking new.