The BOROFUSE® ProcessUnsurpassed wear and corrosion protection
Human ingenuity improving the way you work, live and play.
Think of it as mind over matter. Our solution specialists at MDC developed the BOROFUSE boriding process to combat wear of metal and metal composite work components. Boriding, also known as boronizing, is a thermochemical surface hardening process that diffuses boron atoms directly into the parent material to create an extremely hard, wear-resistant surface. The result is superior stability and durability, extending the life of high performance equipment by protecting it against harsh environmental conditions.
Since it was founded in 1969, the focus of MDC has been to produce high quality boride components and brazes to meet the exacting requirements of the aerospace, oil & gas, injection molding, food processing and military product industries. The sole focus of the company on boron diffusion has led to a vast amount of experience developing new products and processes for customers around the world, as well as resulting in MDC becoming a market leader in boriding services.
Boriding is the common name for diffusing boron into an appropriate substrate. Diffusion is a process which requires an available ion present at a suitable concentration for a period of time at a specific temperature. These conditions are a function of the crystal lattice of the substrate and the diameter of the ion. Once the concentration of the diffused ion, within the substrate, reaches the solubility limit the ion begins to form compounds with the constituent elements of the material. These metal borides form complex phases and compounds which lead to the increase in hardness and dictate the properties of the surface. MDC has, through its extensive experience, established specific conditions and processes to boride a wide variety of materials.
The Boride Layer
The boron diffusion layer, or case, that forms on the substrate can be characterized by depth, hardness and internal stresses; which result from the formation of complex compounds and phases. The depth is thin relative to other diffusion surface modifications and is typically between 0.0003” – 0.007”. The hardness of a typical boride case varies from 1300 – 1900VHN, which is similar to the hardness of tungsten carbide. The stability of such a thin hard surface is derived from the biaxial compression stresses induced during the diffusion and cooling process. These key features; case thickness, hardness, and internal stresses make boriding a robust surface modification for many key components.
The result of the boriding process is a thin surface layer (0.0003″ – 0.007″) of dense metal boride with hardness values ranging from 1300 VHN to 1900 VHN. For iron and nickel based components the hardness increase is large and offers superior wear properties when compared to the base material alone. In the case of cemented carbides, the boride layer consists of the original carbide with a boride formed with the binder; which improves erosion and wear properties of the parent metal. In addition to mechanical property improvements, the boride layer also decreases the corrosion potential for non-ferrous alloys as compared to the base material.
Using a surface modification to improve an existing design or component has the ability to extend life and reduce maintenance costs. Increasing hardness of the surface of a wear component reduces the expected wear of the base material; Borofuse is the solution to many complicated wear problems. With proper implementation in the right conditions and environment an increase if component life of over 10 times can be achieved.
In many environments, boride can provide increased corrosion resistance. The ability of a BOROFUSE processed metal to resist corrosion is dependent upon the base metal composition as well as the specific chemical environment involved. Generally, it can be stated that substantial improvements are achieved for BOROFUSE processed components exposed to hydrochloric acid, hydrofluoric acid, sulfuric acid and sour gas (H2S), while no protection is afforded in nitric acid or against the normal corrosion (rust) of ferrous alloys. The Oil and Gas Industry has benefited greatly from borided components which are incorporated in assemblies used for drilling as well as for other down-hole applications.