The idea of innovative ceramic spraying

       When two objects touching each other move along the tangent direction of the touch surface or have a tendency to move relative to each other, a "conflict" occurs between the touch surfaces. Conflict is a physical phenomenon of accompanying movement. For example, a "spirit" has been with human beings since the birth of human beings. Without this elf, human beings will "walk with difficulty". But in many cases, humans have to contend with this "elf", because the "elf" will become a "conflict monster". "Conflict monsters" will cause wear and tear on the touch surface of objects, and severe wear and tear will make the normal working movement arrangement invalid; moreover, the conflict will consume too much power and bring huge economic losses. Therefore, in order to defeat this "conflict monster", people have thought of many ways to reduce or weaken the destructive power of the "conflict monster". A useful way is to feed the "conflict monster" a medicine, which is what we often call a lubricant.







The shape of this "drug" is similar to the drugs that humans eat, and it is also divided into liquid and solid. Liquid drugs contain various smooth oils, while solid drugs include graphite, molybdenum disulfide and so on. These "drugs" can greatly reduce the power of "conflict monsters" and save a lot of resources and power for human beings. But in some special cases, even if the "drug" is fed to the "conflict monster", its effect is not very significant or useful. For example, when ceramic materials are in conflict, there will be many ground debris, which will make all kinds of lubricants, especially solid lubricants, not very effective. Therefore, how to effectively reduce the wear and tear of ceramic materials, so that the ceramic "conflict monsters" cannot exert their damage power recklessly, has become a difficult problem for human beings in the field of science and technology.







The team of researcher Zhou Huidi from Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences has been devoted to the research on the technology and function of thermal sprayed ceramic-based coating for a long time. Recently, the team used the internal microscopic pores or cracks of the thermal sprayed ceramic coating itself to grow nanosheet-like MoS_{2} with smooth properties in-situ within these pores and cracks through the hydrothermal reaction method. This method realizes the effective introduction of lubricants on the conflicting surface, and corrects the original defects of the conflicting surface of the ceramic coating. Finally, the effective smoothing between the ceramic coating and the metal pair is achieved, and the effect of the coating on the metal is obviously reduced. Dual wear.







On the basis of this research, in order to obtain ceramic matrix composite coating materials with super longevity, low friction coefficient and better wear performance, inspired by the structure of animal cancellous bone and the nutrient mechanism of articular cartilage, the researchers turned their attention to bionics It is expected to transplant and imitate the excellent conflictological characteristics of natural biological systems. The researchers used the thermal spraying process to prepare a biomimetic smart coating with excellent anti-collision function, that is, the surface of the sprayed ceramic coating was laser textured to obtain regularly arranged holes, and then in these holes. Introduce high-performance smooth materials. Finally, the obtained ceramic coating can maintain a low collision coefficient under a wide range of collision rate and load changes, and the collision coefficient can reach <0.065 under high load (1.4 GPa), and has an excellent collision life. (>1×10^{6} turns). During the long-term conflict test, the coating can perform the "self-correcting/adaptive" function of similar biological structures, showing the characteristics of near-zero wear, and the damage to the dual material is extremely small. This excellent conflict theory The function is due to the fact that the ceramic composite coating uses conflict heat and pressure as the driving force and correction force, and forms a smooth transport film like a "cartilage layer" that can be continuously corrected on the surface of the conflict.







The above research ideas and effects are not only applicable to ceramic coating materials, but also to all ceramic materials, opening a window for future research in this field. The above related achievements have been recently announced in Ceramics International, 2017, 43(9):6976-6986, Materials Letters 193 (2017)199–202 and ACS Applied Materials & Interfaces (DOI: 10.1021/acsami. 7b03986).



The above research work has been supported for a long time by the "Youth Innovation Promotion Association (2014378)" of the Chinese Academy of Sciences and the "Light of the West" category A talent training project for young scholars in the west.