High-performance alumina ceramic development status and application of analytical preparation technology to teach!

1. A brief introduction to alumina ceramics

Mainly divided into high purity type: Al2O3 content > 99.9%, sintering T up to 1650-1900℃; And common type (75-99%) : 75 porcelain, 85 porcelain, 90 porcelain, 99 porcelain, etc.

Crystal type -- 12 kinds of isomorphic variants, α, β, γ, δ, ε, ζ, η, θ, κ, λ, ρ and amorphous alumina, and the most common ones are α -al2o3, β -al2o3 and γ -al2o3

2. Preparation technology of alumina ceramics

Raw material processing: using green and efficient processing technology and high-energy equipment, including high purity, ultrafine, distribution, morphology.

Sintering, including the firing system -- the shortest firing curve (heating, insulation, cooling) at the lowest firing temperature to obtain the best performance, atmosphere: inert, oxidation, reduction, vacuum, air; Pressure; Firing methods (hot pressing, hot isostatic pressing, microwave heating, discharge plasma, self-ignition)

Molding technology includes dry, plastic, wet, additive manufacturing (3D printing)

The new technology of plastic processing technology appears in precision machining link: grinding + laser, grinding + ultrasonic

Ceramic additive manufacturing (3D printing) 3D printing technology, also known as additive manufacturing, rapid prototyping, molding and so on.

Based on THE 3D digital model, the technology of layered manufacturing and layer by layer stacking to form a THREE-DIMENSIONAL entity (laminated molding method)

According to the latest report by Grand View Research, the global ceramic 3D printing market is expected to reach nearly $160 million by 2025. The ceramic 3D printing market for an aerospace terminal uses is expected to reach $26.1 million by 2025. The annual growth rate of health-related demand is about 35.4 percent

3. Properties and applications of alumina ceramics

High mechanical strength, good electrical insulation, high hardness and melting point, good corrosion resistance, excellent chemical stability, and under certain conditions has good optical and ionic conductivity.

A wide range of applications, mainly used in mechanical, electronic, electric power, chemical, medical aspects.

Mechanical (high strength, high hardness, wear) - cutting tools, ball valves, abrasives, bearings, drawing, and spinneret parts

Alumina ceramic tools: hard cutting, high-speed dry cutting, super high-speed cutting

High heat resistance, high hardness and wear resistance and excellent chemical stability, and other advantages, is one of the most important cutting tools, the processing efficiency than the traditional tool 3-10 times higher alumina ceramic industrial valve (seal)

Plug valve: petroleum exploitation, transportation, and refining equipment, but also widely used in petrochemical, coal chemical, natural gas, and other industrial fields

Gate valve, globe valve: tap water, sewage, construction, petroleum, chemical industry, food, medicine, light textile, electric power, shipping, metallurgy, energy system, etc

Ball valve: especially suitable for such as oxygen, hydrogen peroxide, methyl, ethylene, strong acid and another bad working medium

Electronics, electric power (high strength, good insulation) - substrate, transparent ceramics, electrical insulation porcelain, spark plug, etc

Alumina ceramic substrate (high-temperature resistance, high electrical insulation performance, low dielectric constant and dielectric loss, high thermal conductivity, good chemical stability)

The post insulator (high strength, high resistance, high dielectric strength, low dielectric constant and dielectric loss, good chemical stability)

Chemical industry (high-temperature resistance, good chemical stability, strong acid, and alkali and organic solvent corrosion) - chemical fillers, foams, honeycomb, microporous, mesoporous ceramics (membranes), corrosion-resistant coatings, etc. - filling, support, and purification of separation materials

Chemical packing (high-temperature resistance, corrosion resistance, high specific surface)

Different structures and shapes: Rasch ring, Bauer ring, cross baffle ring, step ring, moment saddle ring, different saddle ring, etc. It is widely used in drying towers, absorption tower, cooling tower, washing tower and regeneration towers in the chemical industry, metallurgy industry, gas industry, and oxygen industry

Ceramic membrane (high specific surface area, high-temperature resistance, corrosion resistance) -- environmental protection, biochemistry, food and medicine, catalytic reaction, chemical industry, metallurgy, water treatment, seawater desalination, etc

Medical (high strength, high hardness, good chemical stability, biological inertia) -- artificial bone, artificial joint, artificial teeth, and other

Al2O3 -- HAP composite -- good biological characteristics, stable physical and chemical properties, its hardness, bending strength, fracture toughness are close to human bone -- is expected to become the most ideal bone graft material

4. Opportunities and challenges

The stage of high-quality development: a critical period for transforming the growth model, improving the economic structure, and transforming growth drivers

The current situation of China's new material industry: the overall performance is "big but not strong", reflected in the following points

The product structure is not reasonable

There is a serious shortage of high-end materials

Low-level redundant construction, low-end varieties overcapacity

Ministry of Industry and Information Technology: A survey of more than 130 key materials shows that 32% are in domestic blank and 52% rely on imports -- "2018 Expert Forum of National Manufacturing Power"

The core technology is controlled by others, and the transformation of achievements is slow

The core technologies in some fields are controlled by the United States, Japan, and Germany, and a large number of key parts and equipment are still dependent on imports

The international market competitiveness is weak

The cooperation between enterprises and regions is not sufficient

In addition to some backbone enterprises' technology and equipment approaching or reaching the international advanced level, most small and medium-sized enterprises are backward in technology and equipment

Attach importance to the development of new materials industry: at present, a new materials development policy pyramid has been built through programmatic documents, guiding documents, planning development goals and tasks

New materials, including alumina powder and high-performance alumina ceramics, are key base raw materials! It is an important and indispensable support for energy conservation and environmental protection, a new generation of information technology, aerospace, and so on. High-end alumina powder, as well as new materials including high-performance ceramics extending the industrial chain, have great potential.