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AdValue technology supplies high-purity alumina powders produced with an enhanced Bayer process. Our alumina powders feature good chemical stability, a high melting point, superior mechanical strength and hardness, as well as good thermal conductivity and outstanding electrical insulation.
Our high-purity alumina powders can be used in a wide range of advanced applications, such as
| Grade | MG-40 | MG-3 | MA-40 | MA-5 |
|---|---|---|---|---|
| Crystal Structure | γ | γ | α | α |
| Purity Al2O3, ≥% | 99.995 | 99.995 | 99.995 | 99.995 |
| Average Particle Size (D50), µm | 30~40 | 1~3 | 30~40 | 3~5 |
| Specific Surface Area, m2/g | 45~65 | 50~70 | ≤5 | ≤5 |
| Loose Bulk Density, g/cm3 | 0.55~0.65 | 0.30~0.40 | 0.70~0.80 | 0.50~0.60 |
| Impurity ≤, ppm | ||||
| Na | 30 | 30 | 30 | 30 |
| Ca | 1 | 1 | 1 | 1 |
| Mg | 1 | 1 | 1 | 1 |
| Fe | 1 | 1 | 1 | 1 |
| Si | 20 | 20 | 20 | 20 |
| Ti | 1 | 1 | 1 | 1 |
| Cu | 1 | 1 | 1 | 1 |
AdValue’s high-purity alumina ensures consistent performance and reliability in demanding environments across multiple high-tech industries.
Please feel free to contact us to discuss your application and request a quote.
What is high purity alumina (HPA) powder and how is it different from standard alumina?
High purity alumina (HPA) powder is a highly refined form of aluminum oxide (Al₂O₃) with purity levels typically above 99.99%. Unlike standard alumina, which may contain various impurities, HPA offers exceptional chemical stability, consistent particle size, and superior performance in applications requiring minimal contamination. Its high purity makes it ideal for electronic, optical, and advanced ceramic applications, where even trace impurities can significantly impact the performance of the final product.
What are the typical purity levels available for HPA powder?
HPA powders are available in a range of purity grades, most commonly 99.99% (4N), 99.995% (4N5), and 99.999% (5N). Higher purity grades are used in applications such as LED substrates, semiconductors, and high-performance ceramics, where impurities can affect optical transparency, electrical insulation, or chemical resistance. Selecting the appropriate purity level depends on the sensitivity of the process and the required performance of the final material.
What particle sizes of HPA powder are commonly offered?
HPA powders are typically available in submicron, micron, and nano-sized particles. Common ranges include 0.1–1 µm for fine powders used in optical and electronic applications, 1–10 µm for general ceramic processing, and larger particles for refractory or filler applications. Particle size influences packing density, sintering behavior, and surface area, making it a key factor in determining the suitability of HPA powder for specific processes.
How does particle size affect performance in experiments or production?
Particle size directly affects the reactivity, sintering behavior, and surface area of HPA powders. Finer particles promote faster sintering and higher density in ceramics, while larger particles may reduce shrinkage during firing and improve flowability in bulk processing. Fine and sub-micron high purity alumina powders are widely used in high-performance optical or electronic applications, as they enable smoother surfaces and uniform structures In contrast, coarser powders are often used in refractory or structural applications where dimensional stability, reduced shrinkage, and bulk processability are prioritized over ultra-fine surface precision.
What are the mechanical properties of HPA powder?
HPA exhibits excellent mechanical properties after sintering, including high hardness, compressive strength, and wear resistance. Its good racture toughness, combined with structural integrity, makes it suitable for advanced ceramics, tooling components, and high-strength substrates. These properties also allow HPA-based ceramics to withstand mechanical stress and moderate thermal cycling, supporting reliable performance in both laboratory experiments and industrial production.
What are the thermal properties of high purity alumina powder?
High purity alumina has a high melting point (~2,072°C), excellent thermal stability, and relatively low thermal expansion, making it ideal for high-temperature applications. When properly processed, alumina ceramics maintain dimensional stability and chemical integrity under extreme heat, supporting reliable performance in furnaces, high-temperature reactors, and refractory components. The thermal conductivity of HPA-based ceramics can be influenced by microstructure and density, which are controlled through powder characteristics and sintering conditions.How chemically stable is HPA powder under acidic or basic conditions?
HPA powder is chemically inert in a wide range of environments, including most acids and bases at room temperature. It resists corrosion and does not readily react with common laboratory chemicals, making it suitable for applications requiring minimal contamination. However, it may be attacked by hydrofluoric acid and by highly concentrated or molten alkalis, especially at elevated temperatures., so proper handling guidelines should be followed in highly aggressive chemical environments.
Can HPA powder be used in high-temperature applications?
Yes, HPA is ideal for high-temperature applications due to its high melting point, thermal stability, and mechanical strength. It can be used in furnace components, crucibles, high-temperature insulation, and advanced ceramic fabrication. With relatively low thermal expansion and good thermal stability, HPA-based ceramics can withstand repeated thermal exposure when proper heating and cooling rates are applied, ensuring reliable performance in industrial and research environments.How does HPA powder perform in sintering and ceramic fabrication?
HPA powders are highly suitable for sintering because their high purity and controlled particle size promote uniform densification. Fine HPA powders can achieve nearly full density at lower sintering temperatures, resulting in ceramics with superior mechanical, thermal, and optical properties. During ceramic fabrication, HPA ensures minimal grain growth, smooth surfaces, and excellent structural integrity, making it ideal for high-performance components such as LED substrates, insulators, and advanced structural ceramics.
What are the typical applications of HPA powder in research and industry?
HPA powder is widely used in electronics, optoelectronics, advanced ceramics, and chemical research. Key applications include LED substrates, semiconductor materials, high-purity ceramics, wear-resistant coatings, and optical components. It is also employed in catalysts, transparent ceramics, refractory materials, and other high-performance industrial processes where purity, stability, and mechanical strength are critical.
Is HPA powder suitable for optical and electronic applications?
Absolutely. HPA’s high purity, low impurity content, and uniform particle size make it ideal for optical and electronic applications. It is used in transparent ceramics, LED substrates, laser components, and electronic insulators. Its chemical stability, high dielectric strength, and ability to form smooth, dense sintered ceramics make it especially valuable in devices where precision, conductivity, or transparency is essential.
How should HPA powder be stored to maintain quality and prevent contamination?
HPA powder should be stored in a clean, dry, and sealed container to prevent moisture uptake and contamination from dust or other chemicals. Avoid exposure to high humidity, which can cause agglomeration, and keep the powder away from reactive chemicals. For long-term storage, inert or desiccated environments may be used to preserve particle quality and maintain consistent performance in experiments or production.
What safety precautions are needed when handling HPA powder?
Although HPA powder is chemically inert, fine powders can be respirable and pose inhalation hazards. Proper personal protective equipment (PPE), such as dust masks, gloves, and eye protection, is recommended when handling powders. Avoid generating dust clouds, and use proper ventilation or fume hoods in laboratory or production environments. Following standard handling and disposal procedures ensures safe use of HPA powders.
Can HPA powder be customized in terms of particle size, purity, or doping?
Yes, many suppliers offer custom HPA powders tailored to specific research or production needs. Particle size, distribution, purity level, and dopants can be tailored to optimize sintering behavior, mechanical properties, or optical performance. Customization ensures that the powder performs precisely as required, whether for ceramic fabrication, electronic devices, or specialized research applications.
What are the advantages of HPA powder over other ceramic powders?
HPA powder offers superior purity, chemical stability, thermal resistance, and mechanical strength compared to standard alumina or other ceramic powders. Its low impurity levels prevent contamination in sensitive applications, and its controlled particle size ensures predictable sintering and performance. These properties make HPA ideal for high-tech industries, advanced ceramics, optical components, and electronic materials, where conventional ceramics may fail to meet stringent requirements.
How does HPA powder interact with other materials during mixing or compounding?
HPA powder is chemically stable and compatible with many ceramic, polymer, and composite materials under typical processing conditions. It can be blended without significant reaction, ensuring uniform dispersions in slurries, pastes, or composite materials. Proper control of particle size distribution, surface characteristics, and dispersion methods is important to prevent agglomeration and ensure consistent mechanical, thermal, or optical properties in the final product.
What are the moisture sensitivity and hygroscopic properties of HPA powder?
High purity alumina is slightly hygroscopic, meaning it can adsorb moisture from the air, particularly fine powders with high surface area. Moisture uptake can lead to agglomeration, reduced flowability, and challenges in uniform mixing or sintering. Proper storage in sealed, dry containers and controlled humidity environments is essential to maintain powder quality and ensure consistent results in experiments or production.
How do different synthesis methods (e.g., precipitation vs. calcination) affect HPA properties?
The synthesis method has a significant impact on HPA’s particle size, morphology, surface area, and purity. Precipitation-based HPA typically produces very fine, sub-micron powders with high surface area and excellent purity, enabling low-temperature sintering, high final density, fine and uniform microstructures, and superior surface finish, but it is more moisture-sensitive, prone to agglomeration, exhibits higher firing shrinkage, and requires tighter process control. Calcination-based HPA, by contrast, yields coarser, more crystalline powders with lower surface area, better flowability, lower shrinkage, and a wider processing window, though higher sintering temperatures and/or powder blending are often needed to achieve full density.Choosing the appropriate synthesis route allows manufacturers and researchers to optimize HPA properties for their intended use, whether for sintering, ceramics, or coatings.
Can HPA powder be used in additive manufacturing (3D printing) or advanced ceramics?
Yes, HPA powder is increasingly used in additive manufacturing for high-performance ceramics due to its high purity, chemical stability, and predictable sintering behavior. It is suitable for 3D printing processes such as binder jetting, slurry-based printing, and extrusion of ceramic pastes. After printing and sintering, HPA-based parts can achieve high density, mechanical strength, and thermal stability, supporting the fabrication of complex ceramic geometries in electronics, aerospace, and high temperatureapplications.
How should HPA powder be handled to prevent agglomeration?
Preventing agglomeration involves controlled storage, careful mixing, and, when necessary, appropriate dispersion techniques. Fine HPA powders naturally tend to cluster due to van der Waals forces. Using dispersants, ultrasonic agitation, or wet ball milling in slurries can help achieve uniform particle distribution. Minimizing moisture exposure and static build-up during handling also reduces agglomeration, ensuring consistent flowability and sintering behavior.
What are the electrical insulating properties of HPA powder after sintering?
After sintering, HPA exhibits excellent electrical insulation, with high dielectric strength and low conductivity. This makes it ideal for applications in electronics, substrates for LEDs, insulators, and high-voltage components. Its performance is stable over a wide temperature range, and the low impurity content ensures minimal electrical leakage or interference, even in demanding environments.
Can HPA be used as a substrate or coating material in electronics?
Yes, HPA is widely used as a substrate and coating material in electronics due to its high thermal stability, chemical inertness, and electrical insulation properties. It is commonly employed in LED substrates, semiconductor wafers, thin-film coatings, and protective layers in high-performance electronic devices. Its purity and mechanical strength ensure reliable performance, minimal contamination, and long-term stability in electronic applications.
Are there bulk or large-scale supply options for HPA powder?
Yes, HPA powders are available in bulk quantities suitable for industrial-scale production. Suppliers like AdValue Technology can provide large volumes while maintaining consistent purity, particle size, and quality control. Bulk supply is ideal for continuous manufacturing of ceramics, electronics, optical components, and other high-performance materials, allowing manufacturers to maintain consistent production without frequent reordering.
What is the typical lead time for HPA powder orders?
Lead times for HPA powder depend on the purity, particle size, quantity, and customization requirements. Standard grades and sizes may be available for immediate shipment, while highly specialized powders or large quantities may require several weeks for production and quality assurance. Planning orders in advance and communicating specifications with the supplier helps ensure timely delivery and uninterrupted production or research schedules.
Can HPA powder be used in chemical or pharmaceutical processing?
HPA powder’s chemical inertness, high purity, and thermal stability make it suitable for chemical and pharmaceutical applications. It can be used as a catalyst support, a filler for high-purity formulations, or in processes requiring chemically stable ceramics. Its low impurity content ensures that it does not contaminate products, making it reliable for sensitive chemical reactions and pharmaceutical manufacturing.
How do impurities affect the performance of HPA powder in experiments?
Even trace impurities in alumina can significantly affect optical, electrical, and mechanical properties. For example, iron or silicon contamination can reduce dielectric strength, affect transparency, or interfere with sintering behavior. High-purity HPA powders are designed to minimize these impurities, ensuring consistent performance, reliable experimental results, and high-quality final products in electronics, optics, and advanced ceramics.
What are the recommended methods for dispersing HPA powder in liquids or pastes?
Dispersing HPA powder effectively requires mechanical agitation, ultrasonication, or milling in combination with appropriate dispersants. Proper dispersion prevents agglomeration, ensures uniform particle distribution, and improves sintering or processing outcomes. Solvent choice, pH control, and powder-to-liquid ratios also play critical roles in achieving stable slurries or pastes suitable for coating, printing, or molding applications.
