Господдержка предприятий-производителей строительных материалов
Scientists at the Russian Mendeleev University of Chemical Technology (RHTU) have developed a method for laser welding of dissimilar materials, such as glass with metals, for use in high-tech industries, the university’s press service told RIA Novosti.
“In connection with the steady trend towards miniaturization of optical, analytical and electronic digital devices, one of the important and promising areas is the use of femtosecond lasers for joining parts of dissimilar properties in the production of such devices. Such an innovative welding method was developed at the Department of Glass and Sitalls of the Russian Chemical Technical University named after Mendeleev," the message says.
The essence of the process is to focus laser radiation into a micron-sized area at the boundary of two elements being connected, the press service explained. This leads to local heating of materials and their mutual diffusion, which makes it possible to firmly connect even the smallest parts made of different materials.
As told at the Russian Chemical Technology University, technologies for strong and reliable connection of transparent glasses and crystals with each other, as well as with metals, are of great interest in the creation of aerospace components, fiber devices, high-power laser systems and devices operating in high-temperature or chemically aggressive conditions.
Vladimir Sigaev, head of the Department of Chemical Technology of Glass and Sitalls at the Russian Chemical Technology University, said that scientists were able to demonstrate a strong connection of such dissimilar materials as quartz glass and an alloy of iron and nickel, phosphate glass and magnesium aluminosilicate ceramic glass, as well as the connection of two yttrium-aluminum garnet crystals.
“Despite the fact that the coefficients of thermal expansion of individual components differed hundreds of times, extremely high joint strength was achieved, and analysis of the chemical composition of the welds made it possible to detect clear signs of mutual diffusion of materials, which, in turn, allows for the formation of such a strong joint ", - the press service quotes Sigaev as saying.
Similar methods of joining parts using glass solders, glass cements and glass composites are widely used in vacuum electronics. Moreover, recently, along with the trend towards miniaturization of production, there has been a constant increase in requirements for the purity of the materials used, the university said. It is often necessary to directly connect extremely small parts with significantly different temperature parameters to each other. Under such conditions, the use of ultrashort laser pulses sometimes becomes the only way to connect elements.
As the press service of the Russian Chemical Technology University recalled, the first lasers appeared more than 70 years ago, and today they are used in almost all spheres of life - from medicine to photonics. Barcode readers, printers, rangefinders and gyroscopes operate using lasers. Laser technology is constantly evolving, and over the past two decades, ultrashort pulse lasers, the duration of which is expressed in femtoseconds, have become increasingly used. One femtosecond is just one millionth of a billionth of a normal second.
The special properties of such ultrashort pulses make it possible to locally change the structure and properties of materials by influencing not only the surface of the product, but also within the volume of its internal structure, leading to the emergence of new properties that are not characteristic of the original material.