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Labware & Alumina Crucibles Lab Application | Industrial Applications

What is alumina crucible?

Crucibles are built of high-temperature resistant materials and used in chemistry labs as containers for extremely hot chemical substances. In addition, alumina is frequently utilized in ceramic form due to its strength, inexpensive cost, and capacity to tolerate temperatures of up to 1,600℃ (approx. 2,912℉)..Alumina is the most widely used Fine Ceramic today globally and epitomizes Fine Ceramics. It offers superior mechanical strength, electrical insulation, high frequency retention, thermal conductivity, heat resistance and corrosion resistance. Sapphire is a single-crystal form of alumina.

While aluminum begins to melt at approximately 660℃ (approx. 1,220℉), alumina Fine Ceramics only begin to melt or decompose at temperatures above 1,600℃ (approx. 2,912℉).

When materials are heated, their size and volume increase in small increments, in a phenomenon known as thermal expansion. Expansion values vary depending on the material being heated. The coefficient ratio of thermal expansion indicates how much a material expands per 1℃ (2.2℉) rise in temperature. Alumina fine ceramics have low coefficients of thermal expansion — less than half those of stainless steels.

It is resistant to chemical attacks from most acids and alkaline solutions as well as hydrogen and other reducing gases, with the exception of :
High concentration hydrofluoric acid
Phosphoric acid at boiling point
Potassium hydroxide solution at boiling point
Sodium hydroxide solution
Alkali salt melt

Composition:

Al2O3 Alumina 99.7% with traces of MgO Magnesia and SiO2 Silica.
Maximum usage temperature: 1700°C
Good resistance to thermal shock
High electrical resistivity
Good mechanical resistance

Available products:

Cylindrical crucibles
Conical crucibles
Tubular crucibles
Incineration tanks
Dishes

Zirconium Yttrium stabilized Grinding Balls，ceramic ball, ceramic

What are Yttrium Stabilized Zirconia Beads?

Yttrium stabilized zirconia beads are highly efficient and durable media for attrition and ball milling of ceramic materials. These zirconia beads provide a long-lasting, contamination-free solution for the ceramic grinding and milling industry.
Zirconia’s higher density compared to glass and alumina creates a high grinding efficiency and greatly reduced grinding time. The zirconia beads are perfect for use in wet grinding and high-velocity operations.

The Benefits of Yttrium Stabilized Zirconia

High density – 6.00kg/l
High wear and tear resistance, depending on the milling process – approximately 20 times better than zirconium silicate beads and about 35 times better than soda lime glass beads.
High operating time is achievable
Low contamination of the milling product, therefor usable for high-grade grinding of pigments, dyes, pharmaceutical and cosmetic prducts.
Usable for all modern types of mills and high energy mills (vertical and horizontal).
Excellent crystal structure avoids bead breakage and reduces the abrasion of mill parts.
Resistance to a lot of corrosive liquids. Smooth surface, easy cleaning because of low porousness.
Moreover, zirconia milling media’s thermal stability and ionic conductivity make them suitable for high-temperature ceramic composites and solid oxide fuel cells.

Yttrium Stabilized Zirconia Beads Applications

Colour and Paint Industry: Grinding and dispersion of coating and paint systems, e.g. car paint, corrosion protection, dip paints, industrial and structural paints, wood varnishes, coil coatings.
Ceramic Industry: Grinding and processing of electrical ceramics, e.g. barium titanate, piezo-electric ceramics, sensors, condensers.
Plant Protection: Dispersion of fungicides, herbicides, insecticides.
Cosmetics: Grinding of pigments and solids for lipstick, skin and sun protection creams.
Pharmaceutics: Nano grinding for the production of active substances and supplies substances.
Battery raw materials: Ultra fine grinding and dispersion of battery raw materials for Cathode- and Anode materials, for example Lithium-Ion-Batteries.

How to avoid crushing and excessive wear of zirconia beads?

1. The filling amount of beads shall not exceed the upper limit (85%);
2. Beads of different materials shall be selected for sand mills with different linear speeds;
3. Select beads with appropriate density for slurry with different viscosity;
4. Do not mix beads of different materials;
5. Try to use beads with uniform particle size;
6. Keep low speed when cleaning the sand mill with beads; Mechanical speed regulation adopts inching and stepless speed regulation Low speed zone is adopted (the recommended shaft speed is less than 1000rpm);
7. Regularly screen out old beads less than the lower limit;
8. Regularly check whether there are cracks or grooves at the positions of the sand mill separation device, discharge end cover and dispersion shaft the existence of equal stress concentration area.

Graphite Crucibles: Essential Tools for Melting and Casting Non-Ferrous Metals

1. What is a Graphite Crucible?

A graphite crucible is a container utilized for melting and casting non-ferrous metals like gold, silver, aluminum, and brass. Its exceptional thermal conductivity, high temperature resistance, low thermal expansion coefficient for high-temperature applications, and ability to withstand rapid heating and cooling make it an ideal tool for metal casting. Graphite crucibles are resistant to acids, alkaline solutions, and possess excellent chemical stability.

2. Applications of Graphite Crucibles

Graphite crucibles” excellent heat performance enables quick metal melting for faster production cycles. Their resistance to chemicals and corrosion ensures durability and longevity, making them unaffected by workshop conditions. Graphite crucibles come in numerous shapes, categorized by letters starting from A. Each shape is further divided based on the crucible”s inner diameter (ID), outer diameter (OD), height (H), and specific form. The illustrated crucible is cylindrical with a flat bottom and lacks a spout or lid. Graphite crucibles are employed in fuel-fired, electric, and induction furnaces, as well as for transferring and moving molten metals. They must be designed to meet the temperature, chemical, and physical requirements of the specific operation.

3. Metals Melting in Graphite Crucibles

Silver

Graphite crucibles for melting silver are similar to those used for gold melting and can withstand temperatures exceeding 2000°C or 3632°F. The crucible body is made of natural graphite, retaining its chemical and physical properties. It exhibits a low thermal coefficient and strain resistance to rapid heating or cooling at high temperatures.

Copper-based alloys melted in fuel-fired furnaces are processed using silicon carbide graphite crucibles, chosen for their thermal shock resistance.

Gold

Graphite crucibles for gold melting are made of high-grade graphite, possessing thermal shock resistance, thermal stability, oxidation resistance, and excellent mechanical strength. They are designed to endure temperatures above 2000°C or 3632°F.

Aluminum

Crucibles used for processing aluminum and its alloys range from carbon or ceramic-bonded clay graphite to silicon carbide, as these metals melt within the temperature range of 400°C or 750°F to 1600°C or 2912°F.

Detailed introduction about the Ceramic Grinding Balls

Alumina Beads

Alumina Beads are specially formulated to be used in high-energy mills in which a high degree of fineness is required. They are used in various industrial fields such as inks, paints, advanced ceramics, mining, cosmetics and pharmaceutical industries. They are a perfectly spherical shape with high mechanical properties and high wear resistance at a moderate price.

• Specific Gravity:3.9
• Hardness: Mohs 9, VICKERS (0.5 kg) 1200 ± 50
• Relative Cost: Low to Moderate

Silicon Carbide Balls

Silicon Carbide Balls are very high-cost grinding media that are used for milling same materials (silicon carbide ball to mill silicon carbide materials) to avoid contamination. They are a special order item.

• Specific Gravity: 3.1
• Hardness: KNOOP 2500 kg/mm2
• Relative Cost: Very High

Silicon Nitride Balls

Silicon Nitride Balls are very high-cost grinding media that are used for milling same materials (silicon nitride ball to mill silicon nitride materials) to avoid contamination. They are a special order item.

• Specific Gravity: 3.2
• Hardness: Hv10 = 1300
• Relative Cost: Very High

Zirconium Oxide Balls

Zirconium Oxide Balls (95% ZrO2) are the strongest, best wearing ceramic media for metal-free, pharmaceutical and food processing grinding. These balls have a white, shiny appearance.

• Specific Gravity: 6.0
• Hardness: Hv 1150 kg/mm2
• Relative Cost: High

Alumina Toughened Zirconia Beads

Impact and wear resistance: Toughened ceramics have good toughness at high temperatures, and can be easily handled even when used in equipment with high working intensity. ZTA composite grinding ball has good toughness and is suitable for high temperature and high speed grinding equipment;

• Specific Gravity: 3.2
• Hardness: Hv 1100 kg/mm2
• Relative Cost: High

Thank you for reading our article and we hope it can help you to have a better understanding of different types of grinding media. There are many more grinding media that you can select from for a variety of industrial grinding and milling processes. Keep in mind that the material you want to grind almost always determines the choice of grinding media used.

Application of zirconia Ceramics in Industry 2

Zirconium chemicals, particularly zirconia, have recently garnered significant attention as advanced materials for a wide range of industrial and scientific applications due to their exceptional mechanical, thermal, electrical, chemical, and optical properties.

Zirconia, commonly referred to as zirconium dioxide (ZrO2), is the primary oxide of zirconium. It typically exists as white, odorless, and tasteless crystals that are almost insoluble in water, hydrochloric acid, and dilute sulfuric acid.

With the most prevalent being yttria partially stabilized zirconia (Y-PSZ) and magnesium oxide partially stabilized zirconia (Mg-PSZ)、Zirconia Toughened Alumina (ZTA). Its unique resistance to crack propagation and high thermal expansion make it an excellent material for joining ceramics and metals, including steel. Given its distinctive properties, zirconia is sometimes referred to as “ceramic steel.”

The Aadvantages Of Zirconia Ceramics

• High flexural strength and hardness;
• Excellent fracture toughness – impact resistant;
• High maximum use temperature;
• Electrical insulator;
• Corrosion resistance in acids and alkalis;
• Modulus of elasticity similar to steel;
• Coefficient of thermal expansion similar to iron.

Finally, I hope this article can help you to deepen your understanding of the preferred raw materials for the preparation of zirconia ceramic . If you want to know more about it, please visit our website for more information, we can provide you with zirconia ceramic products and professional knowledge solutions.

How To Choose Zirconia Bead For Grinding

With the increasing fineness requirements of materials, the use of sand mills is becoming more and more common, and there are more grinding media in the market. How to choose a grinding media that is more suitable for its own production process and conditions is a key and laborious matter. Here is a brief analysis of the following aspects.

I. Chemical composition

Grinding media can be divided into glass beads ceramic beads (including zirconium silicate beads composite zirconium beads alumina beads rare earth metal stabilized zirconia beads, etc.), steel balls, etc. according to different materials. Due to the difference of chemical composition and manufacturing process, the crystal structure of the grinding bead is determined. The dense crystal structure ensures the high strength, high wear resistance and low ink absorption of the bead. The different percentage contents of various components determine the specific gravity of grinding beads, and the high specific gravity provides guarantee for high grinding efficiency; the natural wear of the chemical composition of grinding beads in the grinding process will have a certain impact on the performance of slurry, so in addition to considering the low wear rate, the chemical elements to be considered are also factors to be considered. For example, when grinding tape powder or other electronic component slurry, metal elements such as Fe and Cu should be avoided, and grinding beads containing Fe2O3 or CuSO4 are not included in the selection, so choosing zirconium beads is often the general choice in this industry; for example, in the aspect of grinding pesticides, medicine and Biochemistry, heavy metals are the most common elements to be avoided, while PbO is the most common one In a word, some physical properties (hardness, density, wear resistance) determined by the chemical composition of the beads and the pollution of its own abrasion to the slurry are the factors to be considered when choosing the grinding medium.

II.Physical properties

1. Density of grinding medium

Density is expressed by specific gravity (true specific gravity) and bulk weight (false specific gravity) in general documents. The molecular weight and percentage composition of various oxides determine the grinding density. The density of commonly used grinding media is shown in Table 1.

In general, the larger the specific gravity of the grinding beads, the larger the impulse, the higher the grinding efficiency, and the greater the wear of the contact parts (inner cylinder, dispersion plate, etc.) of the grinder, so the matching of the viscosity and flow of the slurry becomes the key. Low density abrasive beads are suitable for low viscosity slurry, and high density abrasive beads are suitable for high viscosity slurry.

2. Particle size of grinding medium

The size of the grinding bead determines the number of contact points between the grinding bead and the material. The larger the contact points of the beads with small particle size under the same volume, the higher the grinding efficiency theoretically. On the other hand, when grinding the materials with large particles in the initial test, for example, for the slurry with 100 microns, the beads with d = 1mm are not necessarily used, because the impulse of the beads can not reach the energy of full grinding and dispersion, At this time, beads with larger particle size should be used.

3. Hardness of grinding medium

Mohs and Vickers are commonly used indexes. The higher the hardness of the grinding beads, the lower the wear rate of the beads does not mean. The hardness of commonly used grinding media and other materials is shown in Table 2.

For example, from the point of view of the wear of the contact parts of the grinding ball to the grinder (such as the dispersing disc, bar pin and inner cylinder), the wear of the contact parts of the grinding ball with large hardness is larger, but the best optimization point can be achieved by adjusting the filling amount of the ball, the viscosity of the slurry, the flow rate and other parameters.

Finally, I hope this article can help you to deepen your understanding of the preferred raw materials for the preparation of zirconia bead . If you want to know more about it, please visit our website for more information, we can provide you with zirconia bead products and professional knowledge solutions.

Application of Alumina Ceramics in Industry

Alumina can be divided into high-purity type and common type. The purity of high-purity alumina Al₂O₃ is greater than 99%, and the sintering temperature is as high as 1650 ° C to 1990 ° C. The purity of ordinary alumina Al₂O₃ is less than 99%, and sometimes Al₂O₃ with a purity of 80% or 75% is also classified as ordinary alumina series.

Alumina-Ceramics

High-purity alumina is the basic material for producing heat-resistant, wear-resistant and corrosion-resistant products. High-purity 99% alumina is usually used to make high-purity alumina crucibles, integrated circuit substrates, special wear-resistant materials, etc., which cannot be achieved by ordinary alumina. Ordinary 95% alumina is mainly used as wear-resistant parts, and 85% alumina is often mixed with some talcum powder to improve electrical properties and mechanical strength. It can be sealed with metals such as molybdenum, niobium, and tantalum, and some are used as electric vacuum devices.

We can customize high purity crucibles in a variety of shapes and sizes, making high purity alumina crucibles perfect for a variety of applications. Including: powder heat treatment, lithium battery cathode material heat treatment, electronic products and phosphor powder sintering, piezoelectric and dielectric electronic material heat treatment, chemical analysis, etc.

Finally, I hope this article can help you to deepen your understanding of the preferred raw materials for the preparation of high-purity alumina crucibles. If you want to know more about it, please visit our website for more information, we can provide you with high-quality alumina crucible; products and professional knowledge solutions.