Titankote™B - Boronizing

Boronizing (also known as boriding) is a high temperature thermo-chemical surface hardening process in which boron atoms are diffused into the surface of a work piece to form complex borides (i.e. – FeB/FeB₂) with the base metal.  There is no mechanical interface between the complex borides and the substrate as this is a true diffusion process.  The resulting case layer has a hard, lubricious surface capable of performing at higher temperatures than most surface treatments.  Practically any ferrous material can be boronized, as well as many Ni, Ti & Co alloys.  However, it is important to note that the higher the content of alloy elements, the slower the diffusion rate.

General Characteristics of Boronizing

• High temperature process (850˚ C/1562˚ F typical for ferrous materials)
• High hardness (1600-1900 HV in ferrous materials) of case layer
• Reduced coefficient of friction (0.4)
• High resistance to temperature (approx. 1200° F)
• Increases resistance to acids (especially Hydrochloric acid)
• Boronized layer can be polished after processing
• Reduced tendency to cold weld
• Suitable for a broad range of materials
• Boronized layer can be selectively applied
• Surface treatment can be uniformly applied to irregular shapes
• Heat treatable materials can be fully hardened after boronizing
• Uniform case depths of diffusion layers are controllable

* – The composition of the diffused layer will vary depending on the base material.  For example, ferrous materials will form FeB/FeB₂; nickel-based alloys will form Ni₄B₃/Ni₂B/Ni₃B; cobalt-based alloys form CoB/Co₂B/Co₃B; titanium-based alloys form TiB/TiB₂.

** – The thickness/depth of the borided layer will vary depending on the base material.  Ferrous materials will develop thicker layers; materials with a higher content of alloy elements tend to produce thinner layers.

*** – The micro-hardness of the diffused layer will vary depending on the base material.  For example, FeB/FeB₂ layers will have a micro-hardness in the range of 1600-1900 HV.  Other elements, such as Ni, Ti and Co, will produce a different hardness range, some even higher than FeB/FeB₂.

**** – The processing temperature will vary depending upon the base material.  The temperature shown in the table is a common processing temperature for ferrous materials.

Suitable Materials for the Boronizing Process

This list is representational, but not all-inclusive:  please contact us with questions regarding your specific application substrate.

*- these materials typically require special processing, and are not available as a standard process.