#Alumina

[alucardfan]

Alucard and mina in Kouta Hiranos old style

[dailyfigures]

Kanzaki Ranko ; THE iDOLM@STER Cinderella Girls ☆ Alumina

[materialsscienceandengineering]

Scientists at the TU Wien and the University of Vienna have uncovered the detailed structure of the aluminum oxide surface, a challenge that has baffled researchers for decades. Aluminum oxide (Al2O3), also known as alumina, corundum, sapphire, or ruby, is one of the best insulators used in a wide range of applications: in electronic components, as a support material for catalysts, or as a chemically resistant ceramic, to name a few. Knowledge of the precise arrangement of the surface atoms is key to understanding how chemical reactions occur on this material, such as those in catalytic processes. Atoms inside the material follow a fixed arrangement, giving rise to the characteristic shapes of crystals. On the surface, however, the structure deviates from that inside the crystal. The strongly insulating nature of alumina hindered experimental studies, and the surface structure evaded precise determination for more than half a century. Researchers at TU Wien and the University of Vienna have now solved the complex structure of the Al2O3 surface, a puzzle listed in 1997 as one of the "Three mysteries of surface science." The research group led by Jan Balajka and Ulrike Diebold recently published their findings in the journal Science.

Read more.

[caffeinated-chaos-bean]

[thefigureresource]

F01 - A-Z:

Release: June 2023

Manufacturer: Alumina

Size: 1/7 scale, 10.1in

[starfirexuchiha]

I’ve been seeing more P5 Death Note AUs back in October so I made this ED 1 parody lol.

I was supposed to finish this around Halloween but life got in the way all well.

Honestly I don’t think that Goro and Light are the same, but I still find the old joke funny 😂

MMD Credits are in the video.

[madmad7]

the WORLD

[www-ceramics]

Making weldable ceramic plates...

[technicalceramicsblog]

Alumina Ceramic: Engineering Marvel with Unmatched Versatility and Performance

Alumina ceramic, scientifically termed aluminum oxide (Al2O3), stands as a paragon of modern engineering materials. It is widely recognized for its exceptional properties and versatility, making it indispensable in numerous high-performance applications. This comprehensive exploration delves into the unique attributes, manufacturing processes, and diverse applications of alumina ceramic, underscoring its pivotal role in advancing technology and industry.

The Exceptional Properties of Alumina Ceramic

Alumina ceramic is celebrated for its remarkable combination of physical, chemical, and mechanical properties, which include:

High Hardness: Alumina ceramic possesses a hardness of 9 on the Mohs scale, nearly as hard as diamond. This high hardness translates to excellent wear resistance, making it ideal for applications where durability is paramount.

Chemical Inertness: It exhibits outstanding chemical stability, resisting corrosion and degradation in harsh environments, including acidic and alkaline conditions. This property is critical for applications in chemical processing and biomedical fields.

Thermal Stability: Alumina ceramic maintains its structural integrity at high temperatures, with a melting point of approximately 2050°C (3722°F). This thermal stability makes it suitable for high-temperature applications such as furnace components and thermal insulators.

Electrical Insulation: Alumina is an excellent electrical insulator, with a high dielectric strength. This property is crucial for its use in electronic substrates, insulators, and components.

Mechanical Strength and Fracture Toughness: While alumina ceramic is inherently brittle, it exhibits high compressive strength and moderate fracture toughness. Advances in material science have enhanced its toughness, expanding its range of applications.

Biocompatibility: Alumina ceramic’s inert nature makes it biocompatible, suitable for medical implants and prosthetics. It does not provoke adverse reactions in the human body, ensuring its safety in biomedical applications.

Manufacturing Processes of Alumina Ceramic

The production of alumina ceramic involves several precise steps, each critical to achieving the desired properties and performance. The key stages in the manufacturing process include:

Raw Material Preparation: The primary raw material, high-purity alumina powder, is derived from bauxite ore through the Bayer process. The purity of the alumina powder is essential, especially for high-performance applications, as impurities can significantly affect the final properties.

Powder Processing: The alumina powder is mixed with additives to enhance its properties, such as sintering behavior and mechanical strength. This mixture is then granulated to form a uniform and flowable powder, suitable for shaping.

Shaping: Various techniques are employed to shape the alumina powder into the desired form. Common methods include uniaxial pressing, isostatic pressing, injection molding, and extrusion. The choice of shaping method depends on the complexity and size of the final component.

Sintering: The shaped green bodies are subjected to high temperatures (typically between 1400°C and 1800°C) in a controlled atmosphere during the sintering process. Sintering densifies the material, reducing porosity and enhancing its mechanical and thermal properties.

Finishing: After sintering, the ceramic components may undergo additional machining, grinding, and polishing to achieve precise dimensions and surface finishes. Advanced machining techniques are employed to produce complex geometries and tight tolerances.

Applications of Alumina Ceramic

The unique properties of alumina ceramic enable its use in a broad spectrum of applications across various industries:

Electronics and Electrical Engineering: Alumina ceramic serves as an essential material in the electronics industry, where it is used as a substrate for electronic circuits and components. Its excellent electrical insulation and thermal conductivity make it ideal for semiconductor devices, insulators, and dielectric layers in capacitors.

Mechanical and Industrial Applications: The high hardness and wear resistance of alumina ceramic make it suitable for cutting tools, bearings, seals, and pump components. It is also used as a lining material for industrial equipment to protect against wear and corrosion.

Biomedical and Dental Applications: In the medical field, alumina ceramic is used for orthopedic implants, dental crowns, and prosthetic components due to its biocompatibility and wear resistance. It is also employed in surgical instruments and diagnostic equipment.

Aerospace and Defense: The high-temperature stability and mechanical strength of alumina ceramic make it valuable in aerospace and defense applications. It is used in thermal protection systems, armor, and engine components that require resistance to extreme conditions.

Chemical Processing: Alumina ceramic’s chemical inertness makes it ideal for use in aggressive chemical environments. It is used in reactors, pipes, and vessels for chemical processing, where it provides excellent resistance to corrosion and wear.

Energy Sector: Alumina ceramic is employed in various energy applications, including insulators for high-voltage power transmission, components in nuclear reactors, and parts of fuel cells and batteries. Its electrical insulation and thermal stability are key to its performance in these applications.

Advantages of Alumina Ceramic

The widespread use of alumina ceramic is attributed to its numerous advantages:

Durability: The high hardness and wear resistance of alumina ceramic ensure a long service life and reduced maintenance costs in demanding applications.

Versatility: Its ability to be fabricated into complex shapes and sizes makes it adaptable for a wide range of applications, from simple components to intricate designs.

Cost-Effectiveness: While the initial cost of alumina ceramic components may be higher than some alternative materials, their longevity and performance often result in overall cost savings.

Environmental Resistance: The chemical stability and high-temperature resistance of alumina ceramic allow it to perform reliably in harsh environments, reducing the need for frequent replacements.

Biocompatibility: Its inert nature makes it suitable for medical applications, reducing the risk of adverse reactions and ensuring patient safety.

Future Prospects of Alumina Ceramic

The future of alumina ceramic is bright, with continuous research and development aimed at enhancing its properties and expanding its applications. Innovations in nanotechnology are expected to improve the mechanical and thermal properties of alumina ceramics, making them even more effective in advanced technologies. Additionally, advancements in additive manufacturing techniques, such as 3D printing, are poised to revolutionize the production of complex ceramic components, offering greater design flexibility and efficiency.

Conclusion

Alumina ceramic represents a pinnacle of engineering materials, combining a unique set of properties that make it indispensable across various industries. Its high hardness, wear resistance, chemical stability, and versatility ensure that it remains a material of choice for demanding applications. As technology continues to evolve, alumina ceramic is poised to play an even more critical role in advancing modern engineering and improving the performance and durability of countless products and systems.

[jurph]

Coming Back

A little obsessed with re-entry as a concept these days. The idea of a long cold journey that is arduous, but safe, and all that is required is to endure... followed by a few minutes of being baptized in searing white plasma, no radio communications, some outer layer you thought of as "yourself" being excised as an inevitable cost, a mostly-ballistic trajectory.

It's "mostly ballistic": once you pick your lane, once you shoot your shot, you make the last few trim adjustments with your hydrazine-or-whatever thrusters: and now you've placed your bets. There's not really anything you can do on re-entry where adding energy will help, because the fundamental problem is one of shedding energy. The speed that got you through the journey is now a hazard. You have to re-acclimate to moving slowly. You have to come back, adopt a speed that is more favorable to atmosphere and breathing and humanity, and that means aerobraking. Every part of that is basically deterministic though: too steep and the heat builds up too fast and cooks you; you couldn't absorb the change fast enough. Too shallow and the exposure to heat over dozens of minutes wears you down: you didn't rip the band-aid off fast enough, you overshot your target, you spent so long getting back to normal that you left yourself vulnerable.

So every re-entry trajectory is this Goldilocks thing where you come back, talk to some experts on the far end and say "what is the best way to finish this" and trust them. The final exam is setting your course, knuckling down, and coming through the short dark window of loneliness to a place where you can open the parachutes and splash down safely, and wait for someone to pick you up and say "welcome home. you made it."

[alucardfan]

[dailyfigures]

Toka Kairo ; Original Character ☆ Alumina

[materialsscienceandengineering]

Scientists study effect of boron nitride microribbon on ceramic properties

In recent years, the high complexity of integrated devices has made heat accumulation increasingly critical and has resulted in higher heat dissipation requirements for substrates and packaging materials. In this study, boron nitride microribbon (BNMR)/Al2O3 composite ceramics are prepared using spark plasma sintering (SPS). This study examines the effect of varying the amount of toughened phase BNMR on the density, mechanical properties, dielectric constant, and thermal conductivity of BNMR/Al2O3 composite ceramics while also exploring the mechanisms behind the toughening and increased thermal conductivity of the fabricated ceramics. A team of material scientists led by Ji-Lin Wang from Guilin University of Technology in Guilin, boron nitride microribbon (BNMR)/Al2O3 composite ceramics are prepared using spark plasma sintering (SPS). During the sintering process, the pliable BNMRs were continuously extruded and deformed by the Al2O3 grains under high temperature and pressure, followed by even wrapping of the Al2O3 grains.

Read more.

[caffeinated-chaos-bean]

I know its been around for A WHILE, but if you haven't finished Death Note, this could contain spoilers.