According to foreign media reports, Johns Hopkins University led the development of new metal films. In the future, this material will be used to manufacture micro-electromechanical systems (MEMS) devices such as sensors, and its tensile strength and resistance Heat, high temperature performance than silicon.
Silicon has insufficient heat and pressure resistance
Today's technology is changing with each passing day. Whether it is a car, an Internet of Things, an engine or a public utility, it is inseparable from the support and promotion of micro-sensors. However, the problem is that such sensors are usually made of silicon, but the lack of physical properties of silicon limits its future use.
Kevin J. Hemker, materials scientist and mechanical engineer at Johns Hopkins University, has teamed up with success in the development of new materials that will help ensure that such sensors, known as MEMS, continue. Meet the requirements of future technological frontiers.
Hemker, of Mechanical Engineering at the Whiting School of Engineering, said: "A few years ago, we began experimenting with the use of more complex composite materials to make MEMS devices."
Most micro-electro-mechanical devices (MEMS) have a complex internal structure. Their size is smaller than the width of human hair. The main component is silicon. This type of equipment works well at room temperature, but after moderate heating (heating hundreds of degrees Celsius), the material will lose its strength and its ability to conduct electronic signals. In addition, silicon is brittle and easily broken.
In spite of this, silicon was once the core material of MEMS technology, and its products have survived for several generations. However, this material is not an ideal choice for manufacturers today. In the future, this type of MEMS device will be used in related devices of the Internet of Things technology. Such devices require high temperature resistance and high pressure resistance. Obviously, silicon is not competent for this requirement.
Research and development of new alloy film
Hemker said: "This requires researchers to research and develop advanced materials with greater strength and density, and higher electrical and thermal conductivity. In addition, there is a higher demand for shape maintenance, and its production and shaping must comply with microscopic standards. There are no MEMS materials that meet the above characteristics."
In order to develop such new materials, researchers consider using nickel-containing metals in combination, which is a commonly used advanced structural material. For example, Nickel-base superalloys are used to make jet engines. In view of the demand for shape stability, researchers have done a lot of experiments, they will molybdenum, tungsten, trying to increase the temperature limit corresponding to the thermal expansion of pure nickel.
The John Hopkins University's research team used larger test equipment, similar to the refrigerator, and the team used ions to hit the target, vaporize the alloy and maintain the atomic state, allowing it to accumulate on the surface or substrate. This resulted in a peelable film that eventually produced a freestanding film with an average thickness of 29 microns, which is smaller than human hair.
This kind of independent film has superior characteristics. The film exhibits a very strong tensile strength when subjected to a tensile test, which means that the shape retaining ability is extremely strong without being deformed or broken, and its tensile strength is three times that of the high-strength steel. Although very few other materials have similar tensile strengths, those materials are neither high-temperature resistant nor can they be easily fabricated and fabricated into MEMS parts.
Hemker said: "We think that alloys will help increase their strength and thermal stability, but we don't know how big this effect will be."
Due to the atomic arrangement of the internal crystal structure of the alloy, the strength of the material is particularly high. This structure enhances the strength of the material without affecting the conductive properties of the material.
Hemker said: "The structure makes the alloy film extremely strong and balances the characteristics of the materials. The film is extremely resistant to high temperatures, thermal stability and mechanical stability. The R & D team is busy with the next stage of research and development. Film shaping and manufacturing of MEMS parts. The research group is applying for a patent for this independent alloy film.†(Wen/Li Wenlong)
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