Plasma nitriding

Plasma nitriding is a thermochemical heat treatment process. It hardens the edge layer of a component by enriching it with nitrogen. The process creates a protective layer on the surface and the area close to the surface. It thus improves the wear and corrosion resistance of the components. Since it is conducted at extremely low temperatures, plasma nitriding produces next to no warping. Regardless whether plasma nitriding or other state-of-the-art processes: we optimise even the most challenging technical components for you. As a single part, in custom sizes, or as volume production - whatever your requirements are. Feel free to contact us for a personal, no-obligation consultation.

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The process and its advantages

Plasma nitriding is a heat treatment process in which the edge layer of a workpiece is converted chemically. During this process, nitrogen penetrates the material and forms nitrides. Plasma nitriding and plasma nitrocarburising deliver reliably reproducible outcomes and are superior to other nitriding processes - especially in terms of environmental protection and energy consumption. The process requires no toxic gases, and the energy consumption is reduced substantially.

This is partially because the hardening process is carried out at low temperatures between 350 and 600°C. Warping of the workpieces is also reduced to a minimum, eliminating the need for costly rework, and thus delivering additional cost savings.

Furthermore, plasma nitriding considerably improves a number of workpiece properties, such as service life, corrosion protection, and resistance to fatigue and wear. A partial treatment is also unproblematic. The process is also suitable for subsequent physical and chemical vapour deposition with individual hardness properties, because if necessary a diffusion layer can be created without a compound layer on the surface of the workpiece.

The process is also known by the names of ionitriding, pulse plasma nitriding, cold nitriding, or plasma hardening.



INFO: HLX-1 – process for special surface protection
HLX-1 is defined as a diffusion process that specifically treats the surfaces of components and tools. HLX-1 creates a protective layer that is ideally suited for structured and polished surfaces. In addition, warping is extremely low.


The advantages of plasma nitriding at a glance

  • Improved protection against wear and corrosion
  • Excellent vibration resistance
  • Fewer brittle and porous layers compared with salt bath nitriding and gas nitriding
  • Adaptable layer structure
  • Minimum warping thanks to low process temperature, so reworking of components is unnecessary
  • Partial hardening possible by applying a protective compound or using mechanical means
  • No post-cleaning necessary, because the components receive final cleaning and surface activation in the plasma
  • Short treatment times compared with gas nitriding
  • Alloy steels and stainless steel can be treated with good results

The physics behind the process

Plasma nitriding takes place in a vacuum. An electric field is applied during the process. The workpieces act as the cathode, and the furnace wall is the anode. The added mixture of gas is ionised by the electric field and it envelops the workpieces. The process creates nitrogen-rich nitrides, which disintegrate and enrich the surface with nitrogen.
The surface is activated, and the workpieces are heated. On steels such as stainless steel, the passive layers detach. Generally speaking, the surface receives fine cleaning, because the process sputters off impurity atoms.
The treatment temperature depends on the material type and the desired nitriding hardness depth. The subsequent dwell time ranges between 12 and 50 hours. To equalise the pressure when the treatment is complete, the furnace is flooded with gas. The workpieces cool down.


Areas of application

Plasma nitriding ranks among the most flexible and best nitriding processes. It is generally suited for any type of iron material, but the benefits of the treatment vary with the material.

  • Construction steel: greater protection against wear and corrosion
  • Sintered materials: Operating characteristics and wear protection are improved despite porosity
  • Alloy steels (with a high chromium and aluminium content): particularly improves components subjected to great strain
  • Stainless steel: Wear protection thanks to standard processes with maximum hardness and nitriding hardness depth. Alternative options are long-term, low-temperature processes for high corrosion protection with great surface hardness


Typical components

  • Gear shafts, crankshafts and cam shafts
  • Cam followers
  • Valve components
  • Extruder screws
  • Die cast tools
  • Forging dies
  • Tools for cold forming
  • Injection nozzles
  • Plastic injection moulding tools
  • Long shafts
  • Axles
  • Couplings and engine parts

The nitrided layer and its properties

On the surface, the nitrided layer consists of the compound layer. It is composed of iron nitrides and is more compact and less porous compared with gas nitriding. This layer is followed by the diffusion zone, which is composed of the material and the precipitated nitrides.
If nitriding steel or high-alloy steel with many nitride-forming elements is used, the surface hardness that can be attained also increases accordingly (up to 800–1,200 HV compared to 250-300 HV for non-alloy and 600-700 HV for low-alloy steel). The edge distance having a core hardness of +50 HV is considered to be the characteristic value of the nitriding hardness depth (NHD). This is up to 0.6 mm for non-alloy and low-alloy steels and up to 0.15 mm for high-alloy steels and stainless steel. Influencing factors are the steel used, along with the duration and the temperature of the treatment.

There are variations and enhancements of plasma nitriding, and their use depends on the requirements:

  • Plasma nitrocarburising: for particularly thick compound layers
  • Post-oxidation: further increases corrosion protection on low- and medium-alloy materials

Nitridable steels and treatment outcomes after plasma nitriding

The following results illustrate the effect of plasma nitriding on frequently used materials. Standard and long-term treatments were used. A higher or lower nitriding hardness depth (NHD) and compound layer thickness (CLT) can be achieved by special treatments.

Suitable materials

Select material table
    Nitriding steels
    Case-hardened steels
    Quenched and tempered steels
    Construction steel
    Hot-work steels
    Cold-work steels
    Roller bearing steels
    Spring steels
    Rust and acid resistant steels
    Maraging steels
    Heat resistant steels
    Grey cast iron
    Free-cutting steels
    Sintered metals
MaterialMaterial no.Hardness HV 1NHT in mmVS in μm
32 CrMoV 12-101.7765750-1.0000,2-0,64-15
34 CrAl 61.8504900-1.2000,2-0,54-10
34 CrAl 551.8506900-1.2000,2-0,64-10
34 CrAIMO 51.8507900-1.2000,2-0,54-10
41 CrAIMO 71.8509800-1.0000,2-0,54-10
31 CrMo 121.8515800-1.1000,2-0,54-15
31 CrMoV 91.8519750-1.0000,2-0,54-15
31 CrAIV 791.8523900 -1.2500,2-0,64-10
34 CrAINI 71.8550900-1.2500,2-0,64-15
MaterialMaterial no.Hardness HV 1NHT in mmVS in um
C 151.0401300-4500,2-0,64-15
C15 E/Ck 151.1141250-3500,2-0,64-15
21 MnCr 51.2162600-7500,3-0,64-15
14 NiCr 151.5752500-6500,2-0,64-8
15 CrNi 61.5919500-7500,2-0,84-8
20 NiCrMo 2-21.6523650-7000,2-0,64-8
18 CrNiMo 7-61.6587600-7000,2-0,64-8
16 MnCr 51.7131600-7500,2-0,84-15
16 MnCrS 51.7139600-7500,2-0,84-15
20 MnCr 51.7147600-8000,2-0,84-15
20 CrMo 51.7264850-9500,2-0,84-15
MaterialMaterial no.Hardness HV 1NHT in mmVS in um
C30 E1.1178300-4500,2-0,64-15
C 35 E1.1181300-5000,2-0,64-15
C45 E/Ck 451.1191300-5500,2-0,64-15
C 60 E/Ck 601.1221300-5500,2-0,64-15
40 CrMnMo 71.2311700-8500,2-0,64-15
40 CrMnMoS 8-61.2312700-8500,2-0,64-15
45 NiCr 61.2710600-8000,2-0,54-8
55 NiCrMoV 61.2713600-7000,2-0,64-8
30 CrNiMo 81.6580600-8000,2-0,53-10
34 CrNiMo 61.6582600-8000,2-0,53-10
34 Cr 41.7033500-6000,2-0,54-15
25 CrMo 41.7218600-7000,2-0,54-15
34 CrMo 41.7220500-6000,2-0,54-15
42 CrMo 41.7225600-7500,2-0,54-15
30 CrMoV 91.7707850-9500,2-0,64-15
39 CrMoV 13-91.8523800-9500,2-0,54-8
Toolox33, SP 300siehe 1.2312
Toolox 44800-1.0000,2-0,64-8
ETG® 1001.8523400-6500,2-0,64-8
MaterialMaterial no.Hardness HV 1NHT in mmVS in um
S 235 JR1.1937250-4000,2-0,64-10
S 2351.1938200-3500,2-0,64-10
E 3351.1960300-5500,2-0,64-10
S 235 J2G31.0116350-4000,2-0,64-10
C 105 W 11.1545550-6500,2-0,84-8
C 80 W 21.1625550-6500,2-0,84-8
MaterialMaterial no.Hardness HV 1NHT in mmVS in um
X 38 CrMoV 511.2343900 -1.2500,2-0,44-8
X 40 CrMoV 511.2344900 – 1.2500,2-0,44-8
X 32 CrMoV 331.2365800 – 1.0000,2-0,44-8
X3 NiCoMoTi 18-9-51.2709800-1.2000,15-0,32-4
X 15 CrCoMoV 10-10-51.28861.000 – 1.2000,15-0,32-4
MaterialMaterial no.Hardness HV 1NHT in mmVS in um
X210 Cr 121.2080900 -1.2000,1-0,152-4
62 SIMNCr 51.2101500-6000,3-0,64-8
X 165 CrV 121.22011.000 – 1.2000,1 -0,42-4
115 CrV 31.2210350-5000,3-0,44-8
26 CrMoV 91.2307850-9500,1 -0,44-8
X 100 CrMoV 51.2363800-1.2000,1-0,44-8
85 CrMoV 12-6-51.2364950-1.2000,1-0,44-8
X 155 CrVMo 12-11.2327900-1.2000,1-0,44-8
X 210 CrW 121.2436700-9000,15-0,32-4
X 165 CrMoV 121.2601900 – 1.2000,15-0,22-4
X 60 WCrMoV 9-51.2622800-9000,1 -0,42-4
X 45 NiCrMo 41.2767650-9000,15-0,52-4
90 MnCrV 81.2842450-6500,2-0,64-8
S 10-4-3-101.32071.000 – 1.4000,05-0,25≤3
S 12-1-11.33021.200-1.4000,05-0,2≤3
S 6-5-21.33431.000 – 1.4000,05-0,25≤3
S 18-0-11.33551.000 – 1.2000,05-0,2≤3
MaterialMaterial no.Hardness HV 1NHT in mmVS in um
100 MnCrW 41.2510500-7000,2-0,3≤5
100 Cr 61.3505350-6000,2-0,3≤5
X 102 CrMo 171.35431.000 – 1.2000,1-0,2≤3
MaterialMaterial no.Hardness HV 1NHT in mmVS in um
C75S/Ck 751.1248350-5500,2-0,64-8
60 SiMn 51.5142400-6000,2-0,64-8
67 SiCr 51.7103500-6500,2-0,64-8
50 CrV 41.8159450-6000,2-0,64-8
58 CrV 41.8161450-6000,2-0,64-8
MaterialMaterial no.Hardness HV 1NHT in mm
X 40 Cr 141.20831.000 1.2000,15-0,3
X 38 CrMo 161.2316900-1.2000,15-0,3
X 20 Cr 131.40211.000 – 1.2000,15
X 30 Cr 131.40281.000 – 1.2000,15
X 46 Cr 131.40341.000 – 1.2000,15
X 46 Cr 131.41041.000 – 1.2000,15
X 90 CrMoV 181.4112900-1.1000,15
X 90 CrMoV 181.4117950-1.2000,15
X 35 CrMo 171.41221.000-1.4000,15
X 12 CrNi 1881.4300800-1.2000,15
X5 CrNi 18 101.4301800-1.2000,15
X 10 CrNiS 1891.4305800-1.0000,15
X5 CrNiMo 17 1221.4401800-1.2000,15
X 2 CrNiMo 18 1431.4435800-1.2000,15
X5 CrNiMo 17 131.4449800-1.2000,15
X5 CrNiMo 17 131.45351.000 – 1.2000,15
X 6 CrNiMoTi 17 12 21.4571800-1.2000,15
MaterialMaterial no.Hardness HV 1NHT in mmVS in um
X 2 NICrMo 18 8 51.63591.000-1.2000,15 – 0,31-2
MaterialMaterial no.Hardness HV 1NHT in mm
X 15 CrNiSi 25 201.4841800 – 1.1000,1
X 12 CrNi 25 211.4845800 – 1.1000,1
MaterialMaterial no.Hardness HV 1NHT in mmVS in um
EN-GJL-150/GG 15300-4500,2-0,44-10
EN-GJL-250/GG 25350-5000,2-0,54-10
EN-GJS-400-15/GGG 40EN-JS 1040400-6000,2-0,54-10
GGG 42400-6000,2-0,54-10
EN-GJS-600-3/GGG 60EN-JS 1060500-7000,2-0,64-10
EN-GJS-700-2/ GGG 70EN-JS 1070500-7000,2-0,64-10
MaterialMaterial no.Hardness HV 1NHT in mmVS in um
9 S 201.0711200-3000,2-0,64-8
9 SMnPb 281.0718200-3500,2-0,64-8
10 S 201.0721350-4000,2-0,64-8
45 S 20/46 S 201.0727350-4500,2-0,64-8
44 SMn 281.0762300-6000,2-0,64-8
MaterialHardness HV 1NHT in mmVS in um
Astaloy Mo400-5000,1-0,5
Sint D30350-5000,1-0,55-20
Sint D35150-3000,1-0,35-20