Functional surfaces a key focus at SurfaceTechnology 2015
Functional surfaces are becoming increasingly important for components, implements and utensils of every description. Targeted surface modifications and coatings on base materials can have a profound effect on a product's overall properties such as wear resistance and frictional behavior, thus rendering it more effective for its intended use. Thanks to micro- and nanostructures, even more options are available. Functional surfaces are therefore going to be a special focus at the SurfaceTechnology show to be held this April under the umbrella of HANNOVER MESSE 2015, where the new Micro, Nano & Materials Pavilion will serve as a central point of reference for micro- and nanotechnology users.
In today's material development efforts, cost is another reason why major emphasis is being placed on surface treatments, with many process innovations being driven by new environmental protection requirements. AHC Oberflächentechnik, for example, has developed a process for chrome-plating surfaces and sections thereof in highly selective way. Components to be electroplated are placed in holders that mask out the areas that are not to be plated. "The selective plating process, dubbed SELGA-COAT® CHROM, is significantly more efficient and environmentally friendly than conventional chrome electroplating," explains Jürgen Diesing, Marketing Director at AHC Oberflächentechnik. Plating is performed in a closed system that protects operators and the environment from contact with hexavalent chrome. It also produces no wastewater and operates with almost complete reuse of the process chemicals, so only a very small portion requires disposal. Under the provisions of the EU REACH chemical regulation, there is a general ban on the use of hexavalent chrome after 2017, but SELGA-COAT CHROM is exempt from this.
AHC Oberflächentechnik has also developed an innovative surface treatment process for oxidizing aluminum surfaces without any chemicals, using a laser for selective oxidation (LASOX-COAT®). The laser beam is focused on the surface to be treated in an oxygen atmosphere, causing alloy particles to melt and evaporate. The ionized atoms in the oxygen generated by the laser beam and part of the melted aluminum react to form aluminum oxide (corundum), covering the treated surface with a layer six to ten micrometers thick. The fusion zone is approximately 100 micrometers. "The main advantage of LASOX-COAT® compared to electrolytic processes is the elimination of process chemicals such as acids," says Diesing.
Munich-based POLIGRAT has developed "POLINOX Protect": a particularly environmentally friendly and cost-effective process as an alternative to pickling for stainless steel, which also significantly improves corrosion resistance. Stainless steel pickling is used for the final removal of slag, iron particles and heat tinting from the surface of the material, and to form an intact passivation layer for corrosion protection. This involves chemically removing the top layer of the material, including the damaged passivation layer, using hydrofluoric acid, nitric acid or sulfuric acid, so that a fresh, intact passivation layer can be formed on the clean metal surface. Due to the associated health and environmental risks and the release of heavy metals, pickling is subject to strict regulations for health protection, wastewater treatment and exhaust air cleaning. POLINOX Protect operates on an entirely new principle: instead of removing existing passivation layers as with pickling, the composition and structure of these layers are modified to obtain significantly better corrosion resistance for the treated stainless steel surfaces than with pickling. POLINOX Protect is an aqueous solution containing a special combination of organic, non-toxic active ingredients that do not produce undesirable odors or toxic fumes in use. Says Siegfried Piesslinger-Schweiger, CEO of POLIGRAT: "Treatment with POLINOX Protect improves the resistance of stainless steel to all types of corrosion occurring at temperatures below 250°C."
These three innovative processes on show at SurfaceTechnology 2015 are representative of the wide array of solutions made possible by surface technology. The focus areas in Hall 3 at HANNOVER MESSE include electroplating, industrial paint coatings, plasma surface treatment and micromaterials processing.
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