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Philos Surface Treatments (PST™)

Philos Surface Treatment is a newly developed advanced metal diffusion technology.

The process can be applied to various metals and the low temperature treatment (430-670 C) reduces the risk of material movement or distortion on the final product. This allows for a wider selection of materials to be processed than a conventional Nitriding. The materials we process have a deeper penetration than conventional surface treatments (A conventional treatment has less than a 0.002" depth of penetration compared to 0.003"-0.005" with our PST-05 treatment).

Philos Surface Treatment creates a hardened layer of Rc 72-74 (HV. 1250-1500), more than 0.004" deep. Brittleness is minimized at the surface due to the increase in elasticity with our process versus conventional gas nitriding.

 ** Philos Surface Treatment is not a coating process, it is a diffusion process !!!

Applicable Metal Substrates

  • Carbon Steels: 1010-1050, etc,...  
  • Stainless Steels: 300-400 Series, 17-4 etc...
  • Tool Steels: D2, D2-Modifieds, High Speed Steels (M1-M42), H11-19,
    Modified H-Series, PM Tool Steels, P20, etc...
  • Non-Ferrous: AL, Ti, etc...
For any other metal substrates, please consult one of our sales and engineering support (

Advantages (PST™):

  • Minimal distortion and size change
  • Superior elasticity
  • Excellent heat resistance
  • High Surface Hardness (HRc 73-75) HV 1250-1500
  • Deep Penetration Depth (75µm-125µm; 0.003"-0.005" for PST-05 treatment)



Mainly for cold forming tools and tools with sharp edges.


  • Great penetration depth of 25µm-75µm (0.001"-0.003")
  • Minimizes brittleness of the sharp edges
  • Lasts 2-3 times longer than conventional nitriding, and hard coatings

PST-02 treatment is mainly applied to tooling with sharp edges with diffusion depths of 0.001"-0.003" (25µm-75µm). PST-02 treatment helps to minimize brittleness of the sharp edges so that it is widely used for cold forming and cutting tool applications. The PST-02 treated tools normally last 2-3 times longer than conventional tools. PST-02 treatment can be applied on top of CVD & PVD coatings (TiN, TiCN, TiAlN, etc...), or such coatings can be subsequently applied on top of PST-02 treatment to enhance the tool life.



Mainly for Molds, Dies and machinery parts.


  • Excellent penetration depth  75 µm-125µm (0.003"-0.005")
  • High surface hardness of (HRc 73-75; HV 1250-1500)
  • Improved heat resistance compared to standard coatings.

PST-05 treatment is designed for molds, dies, and machinery parts where the diffusion layer (0.003"-0.005") is needed for rigorous wear-resistance. Parts may be easily welded after PST-05 treatment, making repair work less of a burden. Also, distortion and dimensional changes are minimal so that PST-05 treatment is widely used in molds, forging dies, extrusion dies, and precision machinery components.


Features and Benefits Conventional Gas Nitriding vs. Philos Surface Treatment

Conventional Gas Nitiriding PST-05 Surface Treatment
Penetration Depth 0.0005"-0.001" Up to 0.005"
Hardness HRc 62-66 HRc 72-75
Brittleness after H.T. More Brittle Minimal or No Change
Distortion Yes Minimum
Change in Dimension Yes Minimum

Features and Benefits of Philos Surface Treatment

Features Benefits
1. Increases Surface Hardness up to HRc 72-75 1. Longer life due to increased resistance to wear, heat and corrosion
2. Applicable for many different metals 2. Heat treat all tool steels, stainless steel, aluminum, and others
3. No warping or twisting of the product 3. Eliminates need to machine or grind after heat treating
4. Low temperature process 4. No geometric distortion or warping
5. Ability to surface treat large sizes 5. Large mold and die cavities can be surface treated
6. Short cycle time 6. Quick turnaround
7. Ability to surface treat through PVD & CVD coatings (TiN, TiAlN, etc...) 7. Increase the hardness of PVD & CVD coated tools and parts without affecting the geometry or surface coating
8. Hardness to a depth of up to 0.005" (0.125µm) 8. Longer Life
9. Precise surface treatment times 9. Consistent product bath to bath
10. Minimal discoloration 10. Aesthetically attractive

Applications of PST™ / TNHT™

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