Applications

Metallic materials are materials with properties such as luster, ductility, easy conductivity, and heat transfer. They are generally classified into two types: ferrous and nonferrous metals. Ferrous metals include iron, chromium, manganese, etc. [1]. Among them, steel is the basic structural material and is called the "skeleton of industry". So far, steel still dominates the composition of industrial raw materials. Many steel companies and research institutes use the unique advantages of SEM to solve production problems and assist in the development of new products. SEM with corresponding accessories has become a favorite tool for the steel and metallurgical industry to conduct research and identify problems in the production process. With the increase in SEM resolution and automation, the application of SEM in material analysis and characterization is becoming more and more widespread [2].     Failure analysis is a new discipline that has been popularized by military enterprises to research scholars and enterprises in recent years [3]. Failure of metal parts can lead to degradation of workpiece performance in minor cases and even life safety accidents in major cases. Locating the causes of failure through failure analysis and proposing effective improvement measures is an essential step for ensuring the safe operation of the project. Therefore, making full use of the advantages of scanning electron microscopy will make a great contribution to the progress of the metallic materials industry.   01 SEM Observation of the Tensile Fracture of Metals   Fracture always occurs at the weakest point in the metal tissue and records much valuable information about the whole process of fracture. Therefore, the observation and study of fracture have been emphasized in the study of fracture. The morphological analysis of the fracture is used to study some basic problems that lead to the fracture of the material, such as the cause of fracture, the nature of the fracture, and the mode of fracture. If the fracture mechanism of the material is to be studied in depth, the composition of macro-areas on the fracture surface is usually analyzed. Fracture analysis has now become an important tool for failure analysis of metallic components.   Figure 1. CIQTEK SEM3100 Tensile Fracture Morphology   According to the nature of the fracture, the fracture can be roughly divided into brittle fracture and ductile fracture. The fracture surface of a brittle fracture is usually perpendicular to the tensile stress, and from the macroscopic point of view, the brittle fracture consists of a glossy crystalline bright surface; while the ductile fracture usually has a tiny bump on the fracture and is fibrous.   The experimental basis of fracture analysis is the direct observation and analysis of the fracture surface's macroscopic morphology and microstructural characteristics. In many cases, the nature of the fracture, the locatio...

Recently, global oil prices have risen sharply and the renewable energy industry represented by solar photovoltaic (PV) power generation has received widespread attention. As the core component of PV power generation, the development prospects and market values of solar PV cells are the focus of attention. In the global battery market, PV cells account for about 27%[1]. The scanning electron microscope plays a great role in enhancing the production process and related research of PV cells.     PV cell is a thin sheet of optoelectronic semiconductor that converts solar energy directly into electrical energy. The current commercial mass-produced PV cells are mainly silicon cells, which are divided into monocrystalline silicon cells, polycrystalline silicon cells and amorphous silicon cells.     Surface Texturing Methods for Solar Cell Efficiency Enhancement   In the actual production process of photovoltaic cells, in order to further improve the energy conversion efficiency, a special textured structure is usually made on the surface of the cell, and such cells are called "non-reflective" cells. Specifically, the textured structure on the surface of these solar cells improves the absorption of light by increasing the number of reflections of irradiated light on the surface of the silicon wafer, which not only reduces the reflectivity of the surface, but also creates light traps inside the cell, thus significantly increasing the conversion efficiency of solar cells, which is important for improving the efficiency and reducing the cost of existing silicon PV cells[2].     Comparison of Flat Surface and Pyramid Structure Surface Compared to a flat surface, a silicon wafer with a pyramidal structure has a higher probability that the reflected light from the incident light will act again on the surface of the wafer rather than reflecting directly back into the air, thus increasing the number of light scattered and reflected on the surface of the structure, allowing more photons to be absorbed and providing more electron-hole pairs.    Light Paths for Different Incident Angles of Light Striking the Pyramidal Structure   The commonly used methods for surface texturing include chemical etching, reactive ion etching, photolithography, and mechanical grooving. Among them, the chemical etching method is widely used in the industry because of its low cost, high productivity, and simple method[3]. For monocrystalline silicon PV  cells, the anisotropic etching produced by alkaline solution on different crystal layers of crystalline silicon is usually used to form a structure similar to the "pyramid" formation is the result of anisotropy of alkaline solution on different crystal layers of crystalline silicon. The formation of the pyramid structure is caused by the anisotropic reaction of alkali with silicon[4]. In a certain concentration of alkali solution, the reaction rate of OH- with the surface of Si...

Metallic materials are materials with properties such as luster, ductility, easy conductivity, and heat transfer. It is generally divided into two types: ferrous metals and non-ferrous metals. Ferrous metals include iron, chromium, manganese, etc. So far, iron and steel still dominate in the composition of industrial raw materials. Many steel companies and research institutes use the unique advantages of SEM to solve problems encountered in production and to assist in research and development of new products. Scanning electron microscopy with corresponding accessories has become a favorable tool for the steel and metallurgical industry to conduct research and identify problems in the production process. With the increase of SEM resolution and automation, the application of SEM in material analysis and characterization is becoming more and more widespread.   Failure analysis is a new discipline that has been popularized by military enterprises to research scholars and enterprises in recent years. Failure of metal parts can lead to degradation of workpiece performance in minor cases and life safety accidents in major cases. Locating the causes of failure through failure analysis and proposing effective improvement measures are essential steps to ensure safe operation of the project. Therefore, making full use of the advantages of scanning electron microscopy will make a great contribution to the progress of the metal material industry.     01 Electron microscope observation of tensile fracture of metal parts        Fracture always occurs in the weakest part of the metal tissue and records much valuable information about the whole process of fracture, so the observation and study of fracture has always been emphasized in the study of fracture. The morphological analysis of the fracture is used to study some basic problems that lead to the fracture of the material, such as the cause of fracture, the nature of fracture, and the mode of fracture. If we want to study the fracture mechanism of the material in depth, we usually have to analyze the composition of the micro-area on the surface of the fracture, and fracture analysis has now become an important tool for failure analysis of metal components.     Fig. 1 CIQTEK Scanning Electron Microscope SEM3100 tensile fracture morphology   According to the nature of fracture, the fracture can be broadly classified into brittle fracture and plastic fracture. The fracture surface of brittle fracture is usually perpendicular to the tensile stress, and the brittle fracture consists of glossy crystalline bright surface from the macroscopic view; the plastic fracture is usually fibrous with fine dimples on the fracture from the macroscopic view.   The experimental basis of fracture analysis is the direct observation and analysis of the macroscopic morphological and microstructural characteristics of the fracture surface. In many cases, the nature of the f...

Electron spin sensors have high sensitivity and can be widely used to probe various physicochemical properties, such as electric field, magnetic field, molecular or protein dynamics, and nuclear or other particles. These unique advantages and potential application scenarios make spin-based sensors a hot research direction at present. Sc3C2@C80 has a highly stable electron spin protected by a carbon cage, which is suitable for gas adsorption detection within porous materials. Py-COF is a recently emerged porous organic framework material with unique adsorption properties, which was prepared using a self-condensing building block with a formyl group and an amino group. prepared with a theoretical pore size of 1.38 nm. Thus, a metallofullerene Sc3C2@C80 unit (~0.8 nm in size) can enter one of the nanopores of Py-COF.   A nanospin sensor based on metal fullerene was developed by Taishan Wang, a researcher at the Institute of Chemistry, Chinese Academy of Sciences, for detecting gas adsorption within a porous organic framework. The paramagnetic metal fullerene, Sc3C2@C80, was embedded in the nanopores of a pyrene-based covalent organic framework (Py-COF). The adsorbed N2、CO、CH4、CO2、C3H6 and C3H8 within the Py-COF embedded with the Sc3C2@C80 spin probe were recorded using the EPR technique ( CIQTEK EPR200-Plus).It was shown that the EPR signals of the embedded Sc3C2@C80 regularly correlated with the gas adsorption properties of the Py-COF. The results of the study were published in Nature Communications under the title "Embedded nano spin sensor for in situ probing of gas adsorption inside porous organic frameworks".     Probing gas adsorption properties of Py-COF using molecular spin of Sc3C2@C8     In the study, the authors used a metallofullerene with paramagnetic properties, Sc3C2@C80 (~0.8 nm in size), as a spin probe embedded into one nanopore of pyrene-based COF (Py-COF) to detect gas adsorption within Py-COF. Then, the adsorption properties of Py-COF for N2、CO、CH4、CO2、C3H6 and C3H8 gases were investigated by recording the embedded Sc3C2@C80 EPR signals. It is shown that the EPR signals of Sc3C2@C80 regularly follow the gas adsorption properties of Py-COF. And unlike conventional adsorption isotherm measurements, this implantable nanospin sensor can detect gas adsorption and desorption by in situ real-time monitoring. The proposed nanospin sensor was also used to probe the gas adsorption properties of metal-organic framework (MOF-177), demonstrating its versatility.     Relationship between gas adsorption properties and EPR signals     Effect of gas pressure on EPR signal     EPR signal line width analysis   Spin-based sensors have attracted considerable attention owing to their high sensitivities. Herein, we developed a metallofullerene-based nano spin sensor to probe gas adsorption within porous organic frameworks. For this, spin-...

Environmental catalysts are broadly defined as all catalysts that can improve environmental pollution. In recent years, environmental protection has become more and more popular, and the research and application of environmental catalysts have become more and more in-depth. The environmental catalysts for processing different reactants have corresponding performance requirements, among which the specific surface area and pore size are one of the important indexes for characterizing the properties of environmental catalysts. It is of great significance to use gas adsorption technology to accurately characterize the physical parameters such as the specific surface area, the pore volume and the pore size distribution of the environmental catalysts for the research and optimization of their performance.   01Environmental protection catalyst   Currently, oil refining, chemical and environmental protection industries are the main application fields of catalysts. Environmental catalysts generally refer to the catalysts used to protect and improve the surrounding environment by directly or indirectly treating toxic and hazardous substances, making them harmless or reducing them, broadly speaking, catalysts capable of improving environmental pollution can be attributed to the category of environmental catalysts. Environmental catalysts can be divided into exhaust gas treatment catalysts, wastewater treatment catalysts and other catalysts according to the direction of application, such as molecular sieve catalysts that can be used for the treatment of exhaust gases such as SO2, NOX, CO2, and N2O, activated carbon that can be used as a typical adsorbent for the adsorption of liquid/gas-phase pollutants, as well as semiconductor photocatalysts that can degrade organic pollutants, and so on.   02 Specific surface and pore size analysis and characterization of environmental catalysts   Catalyst surface area is one of the important indexes to characterize catalyst properties. The surface area of catalyst can be divided into outer surface area and inner surface area. Since the majority of the surface area of environmental catalyst is inner surface area and the active center is often distributed on the inner surface, generally, the larger the specific surface area of environmental catalyst is, the more activation centers are on the surface, and the catalyst has a strong adsorption capacity for reactants, which are all favorable to the catalytic activity. In addition, the type of pore structure has a great influence on the activity, selectivity and strength of the catalyst. Before the reactant molecules are adsorbed, they must diffuse through the pores of the catalyst to reach the active center on the inner surface of the catalyst, and this diffusion process is closely related to the pore structure of the catalyst, and different pore structures show different diffusion laws and apparent reaction kinetics, for example, the strong selectivity of ...

What is nano alumina? Nano-alumina is widely used in various fields such as ceramic materials, composite materials, aerospace, environmental protection, catalysts, and their carriers because of its high strength, hardness, wear resistance, heat resistance, and large specific surface area [1]. This has led to the continuous improvement of its development technology. Currently, scientists have prepared alumina nanomaterials in various morphologies from one-dimensional to three-dimensional, including spherical, hexagonal sheet, cubic, rod, fibrous, mesh, flower, curly, and many other morphologies [2].   Scanning electron microscopy of alumina nano-particles   There are many methods for the preparation of nano alumina, which can be divided into three main categories according to the different reaction methods:  Solid-phase, gas-phase, and liquid-phase methods [3]. In order to verify that the results of the prepared alumina nanopowders are as expected, it is necessary to characterize the structure of alumina under each process, and the most intuitive of the many characterization methods is the microscopic observation method.   The scanning electron microscope, as a conventional microscopic characterization equipment, has the advantages of large magnification, high resolution, large depth of field, clear imaging, and strong stereoscopic sense, which is the preferred equipment for characterizing the structure of nano-alumina.   The following figure shows the alumina powder prepared under different processes observed using CIQTEK Field Emission Scanning Electron Microscope SEM5000, which contains alumina nanopowders in the form of cubes, flakes, and rods, and with particle sizes of tens to hundreds of nanometers.     CIQTEK Field Emission Scanning Electron Microscope SEM5000   SEM5000 is a high-resolution, feature-rich field emission scanning electron microscope, with advanced barrel design, in-barrel deceleration, and low aberration non-leakage magnetic objective design, to achieve low-voltage high-resolution imaging, that can be applied to magnetic samples. SEM5000 has optical navigation, perfect automatic functions, well-designed human-machine interaction, and optimized operation, and use process. Regardless of whether the operator has extensive experience, he/she can quickly get started with the task of high-resolution photography.   Electron gun type: high-brightness Schottky-field emission electron gun Resolution: 1 nm @ 15 kV  1.5 nm @ 1 kV   Magnification: 1 ~ 2500000 x   Acceleration voltage: 20 V ~ 30 kV   Sample table: five-axis automatic sample table     References.  [1] Wu ZF. Study on the relationship between the morphology and properties of alumina nanoparticles[J]. Journal of Artificial Crystals, 2020,49(02):353-357. doi:10.16553/j.cnki.issn1000-985x.2020.02.024.  [2] Nie Duofa. A brief discussion on the preparation of nanoalumina...

For centuries, mankind has been exploring magnetism and its related phenomena without pause. In the early days of electromagnetism and mechanics, it was difficult for humans to imagine the attraction of magnets to iron, and the ability of birds, fish, or insects to navigate between destinations thousands of miles apart - amazing and interesting phenomena with the same magnetic origin. These magnetic properties originate from the moving charge and spin of elementary particles, which are as prevalent as electrons.    Two-dimensional magnetic materials have become a research hotspot of great interest, and they open up new directions for the development of spintronics devices, which have important applications in new optoelectronic devices and spintronics devices. Recently, Physics Letters 2021, No. 12, also launched a special feature on 2D magnetic materials, describing the progress of 2D magnetic materials in theory and experiments from different perspectives.    A two-dimensional magnetic material only a few atoms thick can provide the substrate for very small silicon electronics. This amazing material is made of pairs of ultra-thin layers that are stacked together by van der Waals forces, i.e. intermolecular forces, while the atoms within the layers are connected by chemical bonds. Although only atomically thick, it still retains physical and chemical properties in terms of magnetism, electricity, mechanics, and optics.     Two-dimensional Magnetic Materials Image referenced from https://phys.org/news/2018-10-flexy-flat-functional-magnets.html   To use an interesting analogy, each electron in a two-dimensional magnetic material is like a tiny compass with a north and south pole, and the direction of these "compass needles" determines the magnetization intensity. When these infinitesimal "compass needles" are spontaneously aligned, the magnetic sequence constitutes the fundamental phase of matter, thus allowing the preparation of many functional devices, such as generators and motors, magnetoresistive memories, and optical barriers. This amazing property has also made two-dimensional magnetic materials hot. The microelectronics industry has encountered bottlenecks such as low reliability and high power consumption, and Moore's law, which has lasted for nearly 50 years, has also encountered difficulties (Moore's law: the number of transistors that can be accommodated on an integrated circuit doubles in about every 18 months). If two-dimensional magnetic materials can be used in the future in the field of magnetic sensors, random memory, and other new spintronics devices, it may be possible to break the bottleneck of integrated circuit performance.    We already know that magnetic van der Waals crystals carry special magnetoelectric effects, and therefore quantitative magnetic studies are an essential step in the research of two-dimensional magnetic materials. However, quantitative experimental studies on...