Expanite offers a sustainable alternative to Teflon®

Expanite offers a sustainable alternative to Teflon®
April 15, 2022

In addition to the technical and commercial advantages, the environmental compatibility and sustainability of the Expanite process play an increasingly important role for customers. Expanite is becoming a popular alternative to conventional fluoroplastic coatings such as Teflon®halar® or Xylane®.

After the discovery of PTFE (polytetrafluoroethylene) – also known as Teflon® – in 1938, it was some time before technically usable applications for this highly inert material opened their way. Today, coatings based on per and polyfluoroalkyl substances (PFAS) are applied, known by their trade names such as Teflon®, Halar® or Xylan® or more generally designated by the abbreviations ECTFE, PFA, FEP, ETFE, PVDF , etc. in many areas to optimize the sliding and anti-stick properties, as well as the wear and corrosion resistance of the components.

Besides the well-known disadvantages of coatings, such as inhomogeneous layer thicknesses, detachment of the layer and increased corrosion attack if the coating is damaged, PFAS-based products have another significant deficit – carbon-fluorine highly stable and therefore not completely degradable. The compounds are harmful not only to humans but also to the environment and can cause cancer, among other things.

Thus, since the early 2000s, there has been a tendency to avoid the use of these materials, especially when it comes to improving resistance to wear and corrosion.

Expanite surface hardening offers a cost effective and durable alternative. Expanite technology is based on a gaseous process in which carbon and nitrogen are diffused on the surface of the component. The otherwise comparable soft and wear-prone stainless steel material hardens up to a factor of 10 and while conventional diffusion processes impact the corrosion resistance of the material, Expanite processes generally improve the corrosion properties of the component.

Durable against wear and seizing

In addition to removing carcinogens, Expanite’s gas-based diffusion process is significantly more energy efficient and environmentally friendly than comparable wear protection processes, and thanks to the vacuum treatment, no Tedious cleaning of the parts, with potentially aggressive chemicals, is not necessary after curing.

“The various cases in which Expanite is used as an alternative to these plastic coatings are widespread and can be found, for example, in the fields of pumps and valves, food and beverage or general industrial applications”, explains Dr. Holger Selg, Application Expert and Expanite DACH Business Manager. “Above all, we increase the wear and seizing resistance of stainless steel components. By hardening the surface, the sliding properties are improved at the same time and, depending on the application, offer a suitable replacement for fluoroplastic coatings.

Expanite technology, specially developed for corrosion-resistant materials, offers a solution for austenitic, martensitic, ferritic and duplex stainless steels, as well as expensive nickel-based alloys such as Inconel and Hastelloy. Additionally, ExpaniteHard-Ti, developed by the Expanite team of experts, is used for titanium grades.

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