Advanced ceramics are everywhere in people's lives

Advanced ceramics is a new material with wide application. When it comes to advanced ceramics, people often think of it as a stone, or only as a container like a teacup. However, modern advanced ceramics can produce electricity or mechanical processes, which have been developed many functional applications.

Under the command of the teacher's password in P.E class, the students will move quickly to the left or to the front. And advanced ceramics, such as piezoelectric ceramics, can also be arranged rapidly under the action of an electric field. When the electric field turns 90 degrees, it immediately follows the direction, and the response time is within milliseconds. In addition, the transfer of charge within the material can be observed. Under the action of the outfield, the function of the ceramic interior is the foundation of many applications.

Piezoelectric ceramics, as the name suggests, it produces electric charges under pressure; the reverse is also true, it produces deformation or vibration under the action of an electric field. Piezoelectric ceramic can be used in the piezoelectric ignition with the piezoelectric effect. When the hand presses the spring on the lighter, the force on the ceramic produces an electric charge. If there is a gap between the slit, this kind of electrostatic pressure will jump fire and form an electric spark, which can ignite the gas and can also be used for projectile detonation and rocket fire.

Piezoelectric porcelain can also be used as a microphone. Under the pressure of human speech, the corresponding telecommunication number of the human voice will be transmitted. A piezoelectric element with a circuit can be a buzzer or an electronic instrument. The piezoelectric element is actually an energy conversion device, the transducer, which enables the conversion of mechanical energy and electrical energy.



Electronic ceramic components are often used in modern life. For example, when people come back to their homes to press the doorbell, the piezoelectric doorbell can make a magpie sound. In hot weather, the fan can be turned on with a piezoelectric remote control; when the weather is cold, the PTC heater can warm the room. The household refrigerator is cooled by the compressor motor, and in which the PTC starter is also used. When watching TV in the evening, first of all, the PTC color eraser removes the image and makes the color image clear. A large number of electronic ceramic components (more than 50%) are used in color TV.

It can be seen from the above that people in modern life have a lot to do with new materials. At present, the production of advanced precision ceramics is very large, and the annual output of piezoelectric ceramics is thousands of tons.

Advanced Indium Tin Oxide Target Embedded in Apple Iphone

With the recent launch of the new generation iPhone X, iphone has once again become the focus of the market. Many people do not know that in the production of iphone display, the core material for the LCD screen to achieve touch is indium tin oxide (ITO) target.

Indium tin oxide (ITO) is a ternary composition of indium, tin and oxygen in varying proportions. Depending on the oxygen content, it can either be described as a ceramic or alloy. Indium tin oxide is typically encountered as an oxygen-saturated composition with a formulation of 74% In, 18% O2, and 8% Sn by weight. Oxygen-saturated compositions are so typical, that unsaturated composition is termed oxygen-deficient ITO. It is transparent and colorless in thin layers, while in bulk form it is yellowish to grey. In the infrared region of the spectrum, it acts as a metal-like mirror. Indium tin oxide is obtained by mixing two oxides of indium trioxide and tin dioxide in a certain ratio, and tin dioxide generally accounts for 10% of the total weight.

Indium tin oxide conductive film is referred to as the "nerve" of the touch LCD screen. In the production process of the liquid crystal panel, the indium tin oxide target is placed in a vacuum environment, and is bombarded with an electron beam, and the generated particles are dispersed on the screen substrate to form a transparent indium tin oxide conductive film. Because of the existence of these conductive films, the liquid crystal display can sense the static electricity of the fingers and realize touch control. When the thickness of the film does not exceed a few hundred nanometers (one nanometer is one-billionth of a meter), 80% or more of visible light can be transmitted, so it does not greatly affect the transparency of glass or plastic. At the same time, this layer of indium tin oxide film has a strong electrical conductivity, and the resistivity can be as low as one ten-thousandth of an ohm•meter. The perfect combination of light transmission and electrical conductivity makes indium tin oxide the only choice for producing touch screens.

Sputtering targets are not only the core materials in the field of flat panel displays, but also widely used in solar cells, electrochromic functional films, infrared remote sensing detectors and other fields. At present, the innovative target atmospheric pressure sintering process solves the problem of high input cost of high-pressure sintering, poor technical stability, and difficulty in large-scale production. In addition, the major sputtering target companies have achieved large-scale, high-density and low-resistivity products, and are committed to improving core performance indicators such as relative density, purity and resistivity.
　　
Nowadays, ITO targets are setting off a new round of enthusiasm, and ITO targets are being further expanded in the fields of high-end thin film transistor liquid crystal displays. For more information, please visit https://www.sputtertargets.net/.

CVD Products Made of Pyrolytic Boron Nitride for Demanding Applications

Pyrolytic Boron Nitride is a boron nitride ceramic product that does not react with acids, bases, organic solvents, molten metals or graphite. It can withstand temperatures of 1800 ° C in a vacuum and 2000 ° C in nitrogen, making it ideal for use as a furnace assembly and melting vessel. PBN crucible heated to 1200 ° C can be inserted into liquid nitrogen without causing significant damage. PBN coated graphite heating elements provide an extremely uniform temperature profile for compound and silicon semiconductor fabrication.
By means of the CVD process, it is possible to produce a component of pyrolytic boron nitride or graphite products with numerous properties, which can provide customers with decisive added value:
In ultra-high vacuum applications, the decarburization of pyrolytic boron nitride at the highest temperatures is minimal.
Pyrolytic boron nitride components not affect the chemical reaction or physical properties of the product being tested.
Components made of pyrolytic boron nitride have good toughness and a stable shape.

Pyrolytic boron nitride crucible
CVD is capable of producing tantalum made of pyrolytic boron nitride of different sizes and forms. Such as:
Straight
Conical shape
Special form
PBN and graphite coating
Using a chemical vapor deposition process, we can coat a suitable graphite material with pyrolytic boron nitride to combine the thermal, chemically stable, and electrically insulating properties of anisotropic PBN with the conductivity of graphite. This means it can make thicker parts such as heaters, furnaces and furnaces.

PBN-PG heater
Since pyrolytic boron nitride and pyrolytic graphite can be combined because they have comparable CTE (coefficient of thermal expansion), they can be used to construct a heating element. The light weight and associated good rapid temperature change behavior, as well as the chemical inertness associated with other substances, should be emphasized here. PBN-PG heater can be manufactured in the form of a planar heater or a 3D heater such as a tube.
For more information, please visit https://www.preciseceramic.com/.

Unexpected Catalytic Activity: Boron Radicals Make Boron Nitride Active

Boron nitride has long been considered a chemically inert ceramic material, but recently, this material has exhibited unexpected activity in the field of catalysis, causing widespread concern. Different morphologies of boron nitride (such as nanosheets, nanotubes) have been successfully used to catalyze some important industrial processes, such as acetylene hydrochlorination and propane dehydrogenation. According to these findings, the catalytic activity of boron nitride is derived from various defects and edge effects in its structure. However, the precise active site and catalytic mechanism of BN are still unclear.



Recently, Yang Wenrong Research Group of Deakin University in Australia cooperated with Chen Ying Research Group to detect the working mechanism of boron radicals and their catalytic reactions in boron nitride nanostructures for the first time. Through chemical experiments and theoretical calculations, they confirmed that boron radicals are active sites for boron nitride catalyzed reactions. Experimentally, the team used boron radicals to quench a stable active free radical (2,2-diphenyl-1-picrylhydrazyl, DPPH), and the density of boron radicals on the surface of boron nitride (nanosheets or nanoparticles) is determined by electron spin resonance (ESR) spectroscopy. Density functional theory (DFT) calculations show that boron radicals are generated at the defects and edges of boron nitride nanosheets. By strong ultrasonic stripping, the authors increased the number of boron-nitrogen bond cleavage and produced more defects and unsaturated boron atoms (boron radicals), which made the quenching effect on DPPH stronger. Interestingly, by comparison experiments, boron nitride was modified with different terminal groups (amino or hydroxyl) without affecting the detected free radical strength and catalytic activity. This further confirms that the active site is a boron radical centered on a boron atom, rather than other groups centered on a nitrogen atom or an oxygen atom.

Subsequently, the research team successfully used boron nitride nanosheets for the catalytic oxidation of hydrogen peroxide to 3,5,3',5'-tetramethylbenzidine (TMB). They found that boron radicals can promote the catalytic decomposition of hydrogen peroxide, and the formed hydroxyl radicals further react with colorless TMB, and are oxidized into a blue, diimine-type product by transfer of their own electrons. The hydroxyl radical generated by the decomposition of hydrogen peroxide can be captured by a 5,5-dimethyl-1-pyrroline N-oxide (DMPO) and determined by ESR spectroscopy. It has been found through experiments that the presence of boron nitride nanosheets promotes the generation of hydroxyl radicals. This study first proposed a catalytic reaction mechanism based on boron radicals, which is a new way for the development of boron nitride in the field of catalysis.

Boron Radicals Identified as the Source of the Unexpected Catalysis by boron Nitride Nanosheets
Zhen Liu, Jingquan Liu, Srikanth Mateti, Chunmei Zhang, Yingxin Zhang, Lifen Chen, Jianmei Wang, Hongbin Wang, Egan H. Doeven, Paul S. Francis, Colin J. Barrow, Aijun Du, Ying Chen and Wenrong Yang
ACS Nano, 2019, DOI: 10.1021/acsnano.8b06978

For more information, please visit https://www.preciseceramic.com/.

Factors Affecting the Quality and Function of Tantalum Film

There are three factors that affect the quality and function of the tantalum film: 1) the nature and structure of the material to be deposited (ie, the metal tantalum), 2) the quality and performance of the source material (ie, the tantalum target), and 3) the inherent performance and layout of the deposition system and its associated peripherals.

The nature and structure of the material to be deposited cannot be changed. The only thing you can do is to change another material, such as aluminum, molybdenum, or else.

Tantalum is dense, ductile, very hard, easily fabricated, and highly conductive of heat and electricity, which is a good coating material. So you don't need to worry about its inherent nature will have bad influence on the deposited film. Also, this article does not discuss the first factor but focuses on the latter two factors.

The sputtering industry has high requirements for source materials. The tantalum target used for sputter coating generally has a purity between 2N and 5N. While for special industries, such as the electronics industry, the purity requirement of the tantalum target is generally before 4N-6N.



In addition to purity, density is also an important measure of the target quality. The density of the target material not only affects the sputtering rate, but also affects the electrical and optical properties of the film. In general, the higher the density of the target material, the better the performance of the film. Additionally, increasing the density and strength of the target material allows the target material to better withstand thermal stresses during sputtering.

Another measure of the quality of the deposition source is the grain size. For the same target material, the sputtering rate of the target having a small grain size is faster than the sputtering rate of the target having a large grain size; the thickness distribution of the target sputtering film having a small grain size difference is more uniform. In order to obtain qualified bismuth targets, we recommend purchasing from Stanford Advanced Materials, a global sputtering target supplier.

After talking about the source material, let's take a look at the deposition system. Undoubtedly, if a sputtering system with poor sealing properties, structural disorder, and old equipment is used for coating, even if the source material is good, a satisfactory film cannot be deposited. Therefore, a well-designed, well-equipped sputtering system is essential. It is still recommended that you purchase a sputter machine from a trusted manufacturer and have regular maintenance to ensure that the system is operating properly.

For more information, please visit https://www.sputtertargets.net/sputtering-target.html.