Topic of the Month June 2010

Figure 1: Pressure distribution on the surface of an aircraft. Source: German Aerospace Center (DLR).

The Surface of Components and Parts – Innovation on Top

Material surfaces are specific areas of components and parts that stand in direct contact with the technical surroundings and the environment. Therefore, they have a special relevance. In addition to important technological features - like hardness, wear and corrosion protection - the quality of a material surface is also a central design feature. Colour, brilliance, texture or certain haptic features are common examples, which bring variety, distinctness, individuality and recognition to the products of different industrial sectors. This central importance is also confirmed by analyzing the statistics of the recently held trade shows wire and Tube. Regarding future product developments and improvements, the subject "surface" is of high priority for 2.400 exhibitors and more than 69.000 visitors. Current results from research labs emphasize this trend - intelligent properties, material efficiency and the integration of various functions are just a few innovations, which will be available in the near future, to equip tubes and wires with optimized and tailored property profiles.

Making Temperature and Pressure Visible

The characterization of the distribution of surface temperature and surface pressure plays an important role in numerous technical systems - especially in the geometrical design of aircraft and automotive components. In order to clarify aerodynamic issues extensive wind tunnel tests are being peformed, in which usually dyes are used, which are either temperature-sensitive or pressure-sensitive. These dyes generally contain toxic substances and they can only be removed in time-consuming cleaning processes. Researchers around Prof. Dr. Otto Wolfbeis of the University of Regensburg can resolve this collective of disadvantages now. As part of their research, they have developed water-soluble, easily washable and environmentally friendly dyes, with which the pressure and temperature distributions on technical surfaces can be measured quickly and simultaneously. The chemists therefore use fluorescent probes containing embedded micro- and nano-particles. These probes can be activated by LEDs or by laser radiation and they generate a pictorial representation of the distribution of surface pressure and surface temperature via occuring fluorescence effects. Currently, the team works on the optimization of the response time of the sensor materials - in the future, they will realize response times of only a few milliseconds.

New Technology will Create Very Thin Gold Coatings

Figure 2: The non-contact sensor detects the heat signal emanating from a finger. Source: Joanneum Research Forschungsgesellschaft mbH.

Gold is one of the rarest raw materials on earth - the proportion of gold in the earth's crust is only about four milligrams per tonne. About three million tons of earth must be moved and processed, in order to gain a ton of gold. This requires an enormous effort with a high energy and material input, which often goes at the expense of the environment. About 15 tons of gold are being processed in Germany alone every year, about 25 percent of it for jewellery and other decorative applications. The German Company Nanocraft Coating from Engen in Baden-Württemberg, which is supported by the Deutsche Bundesstiftung Umwelt, DBU, is now developing completely new processes for gold coatings, which allow the realization of considerably thinner layers of precious metals than before. The company, that is specialized on the investigation of technical surfaces in the nanometer range, is working on two new coating technologies, by which the layers of gold on jewellery articles can be reduced to the half. “We could achieve only 50 percent of the previous thickness at less material consumption, without reducing the durability or the wear behaviour of the pieces of jewellery respectively" said CEO Dr. Sabri Akari. By using this novel technology in the ongoing development, the consumption of precious metal can be reduced up to 80 percent.

Devices with Printed Sensors

The EU project "Printable pyroelectrical and piezoelectrical large area sensor technology" - in short 3Plast, that is coordinated by the Fraunhofer-Institut für Silicatforschung ISC in Würzburg, strives the goal to develop novel pressure and temperature sensors, which can be applied onto the surfaces of various devices and components. The vision of the scientists and engineers is to construct electronic devices, which can be operated by simple finger movements. A direct contact to the surface should no longer be required. Like the human skin, which reacts onto smallest changes of temperature and pressure differences, these new sensors shall detect a finger already if he reaches the user interfaces. Special polymer sensors make such developments possible, by intelligently combining the pyro- and piezoelectric properties and the necessary electronic amplification equipment. Furthermore the involved companies and research institutes plan to develop sophisticated process technologies, by which the sensors can be printed on films inexpensively by mass-production. By offering tailored properties for various applications, markets like automotive engineering, building industry and robotics are being adressed.

Dr.-Ing. Christoph Konetschny
Material and Nano Expert

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