China's instrumentation, electronics, communications and other industries have developed rapidly. Taking OLED as an example, China has become one of the major producers in the world. The international competitiveness of domestic AMOLED is increasing, the capacity is expanding, and the demand for FMM is strong.
Invar alloy, also known as low expansion alloy and invar alloy in Chinese, is a kind of ferronickel alloy, with 36% nickel and 64% iron as the main components, and is in face-centered cubic structure.
The outstanding advantage of Invar alloy is that its coefficient of thermal expansion is very low. In addition, it has the characteristics of low thermal conductivity, high toughness, high reduction of area, good ductility, low strength and hardness, and good plasticity. It is an important structural material.
Invar alloy can be widely used in the manufacturing of various instruments, electronic and communication products, such as optical instruments, microscopes, picture tubes, length scales, resonators, waveguides, standard frequency generators, gyroscopes, clocks, capacitors, cable cores, electronic tubes, thermal bimetallic sheets, metal masks, etc. It can also be used in the aerospace industry, such as artificial satellites, aerospace remote sensors Astronomical telescope and other fields.
The technical barrier of Invar alloy is high, especially the production of products applied in high-end fields is difficult. Taking FMM (fine metal mask) as an example, Invar alloy is the key material for manufacturing FMM. It can be processed into base material, and then covered with PI material for precise opening, which requires Invar alloy less than 30 microns.
FMM is the core component of OLED to form pixels. The higher the performance of OLED, the higher the requirement of FMM's thinness, and the higher the precision of Invar alloy required. Globally, the Invar alloy used in the OLED field is only produced by Hitachi Metals in Japan, and the Invar alloy below 30 microns is not sold.
In addition to the difficult preparation, the processing of Invar alloy is also difficult. Invar alloy cannot be heat treated. Because of its low hardness, high toughness and large plasticity, it is difficult to cut off during cutting and requires large cutting force. Therefore, the cutting temperature is high and the tool wear is serious. To process high-precision workpiece, high-performance tools are required, and the process requirements are high.
More than ten years ago, China's FMM market was monopolized by international FMM giants such as Japan DNP. In recent years, many Chinese technology-based FMM technology enterprises have entered the stage of mass production.
In this context, China must achieve independent supply of key materials, so the pace of research and development and production of Invar alloy needs to be accelerated.
In addition to instruments, electronics, communications and other fields, Invar alloy is also irreplaceable in precision molds, LNG ship storage tanks, LNG transportation pipelines, liquid hydrogen/liquid oxygen containers and other fields.
Globally, the number of high, middle and low end Invar alloy manufacturers is small, especially the production of high-end products is monopolized by a few enterprises. Some manufacturers in Europe and the United States are speeding up the development of Invar alloy for OLED, and have achieved certain results, but have not yet realized industrial production.
In China, some of high-tech enterprises such as SHBG and XAGY have the capacity of mass production of Invar alloy.