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New Type Titanium Aluminum Carbide Ceramic Materials Were Innovated

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Update time : 2020-01-03 11:27:25
Metals are easy to conduct electricity, but they are not resistant to high temperatures, corrosion, and ceramics, but they do not have the excellent conductivity characteristics of metals. Is it possible to concentrate the advantages of metals and ceramics on one material?

In the 1960s, scientists discovered a class of layered ceramic materials with special functions, because they are composed of three types of elements M, A, and X on the periodic table of elements, collectively referred to as "MAX phase," a unique nano-layered crystal structure allows it to have the properties of both metals and ceramics, high conductivity, high-temperature resistance, oxidation resistance, radiation resistance, and corrosion resistance. In short, almost all the excellent properties you can think of have such materials. However, due to technical limitations in preparation and other aspects, such materials have not been widely recognized and applied.

 

We have learned that Luoyang Tongrun's team innovated the preparation method of MAX phase layered ceramic materials, and synthesized a series of new MAX phase materials --- Titanium Aluminum Carbide. The chemical formulas are: Ti3AlC2 and Ti2AlC; these materials are of high quality, which opened a new situation in the field of research and application. In the future, it may be used in nuclear energy storage, flexible display, superconductivity And other fields have obtained good application prospects.

The MAX phase titanium aluminum carbide is an artificially synthesized material; M represents a pre-transition metal element; A represents an IIIA and IVA main group element, and X represents carbon or nitrogen. To some extent, MAX is similar to graphene.

"They are both layered structures. If you magnify graphene by billions of times, we will see that carbon atoms are evenly arranged, and the space group of MAX is similar." The difference is that the MAX phase consists of a densely packed M6X octahedron layer and an A atomic layer.

Structure determines performance. The unique nano-layered crystal structure enables the MAX phase to have both the excellent properties of metals and ceramics, such as high conductivity, high-temperature resistance, oxidation resistance, radiation corrosion resistance, and so on. It is precisely to see the application prospect of this kind of material in many fields. After 1996, related research on this kind of material was widely carried out in Japan, Europe, and China.

The preparation of such materials ( Ti3AlC2, Ti2AlC ) has always been a problem. "In general, in the past, the three types of raw materials, M, A, and X, were burned together; 'There are few types of such materials, and the quality is not good.' Du Jun from Luoyang Tongrun introduced.

 

How did Du Jun's advanced energy materials engineering laboratory team do?

"We have adopted a new synthetic strategy for the precise replacement of A-site atoms," Du Jun said. "In simple terms, we first put together the 'skeleton' of two materials, M and X, and then use some method to carry out the atom. The precise replacement of the lattice site puts the A atom we want with some function in it. "

This method not only completely surpasses the traditional method in terms of ideas but also can be further applied to the preparation of its two-dimensional derivative material MXene in a very environmentally friendly manner. "Traditional methods generally use highly toxic fluoride. We use sodium chloride and potassium chloride, which are common in life. The whole process is very efficient, safe, and green."

Innovative preparation methods and flexible A-site control are also expected to expand MAX phase materials titanium aluminum carbide from pure traditional high-temperature structural applications to high-end advanced functional applications.
"Like gold, it is well known that small particles of gold have higher catalytic activity. If we precisely replace gold atoms into the MAX phase, this material becomes a good catalyst."

We learned that at present, Du Jun's team has successfully prepared a variety of MAX-phase materials ( Ti3AlC2, Ti2AlC ) with element A as zinc in the laboratory, which has opened up a new situation for research in this field.

For more information, please review at www.nanotrun.com.