Semco’s Graphite Treatment Services
Graphite is a versatile and tough material, but like other materials used in industry, it can degrade. Many treatments, including oxidation reduction reactions and PTFE coatings, can help protect the material from corrosion and degradation when it is exposed to extreme conditions, as it often is in manufacturing processes. (“But what is PTFE?” you ask. We’ll get to that.) In this post, we will examine and explain some of these treatment services for graphite material that Semco offers. You’ll have a better idea how best to protect your graphite components, whether it’s with oxidation reduction reactions, phenolic resin, or purification (among other treatments).
This treatment, for use in an oxygen-rich environment at temperatures up to 1,000° F, applies a thin film barrier both externally and on the internal porosity of graphite materials, thereby reducing the eroding effect of oxygen on synthetic graphite binders. Typical uses for this treatment include static casting, glass manufacturing, and molten aluminum processing.
This process will render the base synthetic graphite resistant to acidic and basic solutions. The inherent porosity of the graphite is filled with phenolic resin and then cured to produce a higher density composite material with almost no porosity. Typical uses for this treatment include chemical baths, heat exchangers, anodes, cathodes, and applications requiring the elimination of porosity.
This process, similar to phenolic resin treatment, will render the base synthetic graphite resistant to acidic and basic solutions at lower operating temperatures. The inherent porosity of the graphite is filled with a paraffin and then cured to produce a higher density composite material with almost no porosity. Typical uses for this treatment include chemical baths, heat exchangers, anodes, cathodes, and, in general, applications requiring the elimination of porosity that do not involve high operating temperatures.
This process will allow the open porosity of the synthetic graphite to be filled with a variety of metals depending on the application. Common metal fillers are copper, babbitt, and antimony. Typical uses for this treatment include bushings, bearings, and wear plates.
This process will reduce the total ash and impurities in the synthetic graphite materials to ranges between 20 ppm and 0.05 ppm (depending on the base grade). Typical uses for this treatment include hot zones, crystal and quartz growing, and semiconductor production.
CVD: Continuous Vapor Deposition / Silicon Carbide (SiC) Coatings
Machined graphite components used in semiconductor, solar cell, and LED markets all need CVD/SiC coatings to function properly. CVD/SiC-coated components are chemically inert and thermally stable. A uniform CVD/SiC coating increases the longevity of parts used in production.
If it was you that asked “What is PTFE?”, we’re finally getting around to your question. First, if you want to know literally what PTFE stands for, it’s “polytetrafluoroethylene,” but that doesn’t tell us much (unless if you’re a chemist). PTFE is essentially Teflon, a polymer consisting of carbon and fluorine. The versatility of PTFE coatings allows for almost unlimited application to a wide variety of part sizes and configurations. These coatings, available in both powder and liquid, are valuable for reasons far beyond their inherent nonstick qualities. Combining heat resistance with almost total chemical inertness, excellent dielectric stability, and a low coefficient of friction, PTFE coatings offer a balance of properties unbeatable by any other material.