Advanced Ceramics Is The Most Potential Development In New Materials Field

According to the preparation technology and application field of ceramics, ceramics can be divided into traditional ceramic materials and advanced ceramic materials. Advanced ceramics have gradually become an important part of new materials.

Advanced ceramics: according to chemical composition can be divided into oxide ceramics, nitride ceramics, carbide ceramics, boride ceramics, silicide ceramics, fluoride ceramics, sulfide ceramics, and so on. According to its properties and uses, it can be divided into two categories: energy ceramics and structural ceramics. Functional ceramics are mainly based on the special functions of materials, with electrical properties, magnetic properties, biological properties, thermal sensitivity, optical properties, and other characteristics, mainly including insulating and dielectric ceramics, ferroelectric ceramics, piezoelectric ceramics, semiconductor, and sensitive ceramics, etc. Structural ceramics are mainly based on the mechanical and structural uses of materials, with high strength, high hardness, high-temperature resistance, corrosion resistance, oxidation resistance, and other characteristics.

Advanced Ceramics Is The Most Potential Development In New Materials Field
Advanced Ceramics Is The Most Potential Development In New Materials Field

Structural ceramics with their excellent mechanical and thermal properties become an important branch of ceramic materials, accounting for about 30% of the whole ceramic market. In nearly 20 years, the national major projects and cutting-edge technology in ceramic material and its preparation technology is also put forward higher demands and challenges, such as aerospace rocket liquid hydrogen in liquid oxygen turbine pump use of silicon nitride ceramic bearings under the condition of low-temperature extremes no-slip condition at high speed, requirements at the beginning of the ceramic bearing high strength, good, wear resistance, surface processing of high precision; The large size ceramic sealing ring used in the main pump of nuclear power plant needs long service life and high reliability. In particular, the silicon carbide ceramic reflector used in the ground monitoring of the earth satellite shooting targets, in addition to high elastic modulus, low thermal expansion coefficient, and lightweight, requires high precision ultra-mirror and large size. This is a challenge to the molding technology, sintering technology, and processing technology of large-size structure ceramic materials. In optical communication, the inner hole of the optical fiber connector is 125 microns, and it requires a very high surface finish, dimensional accuracy, and concentricity. So Structural ceramics is the most promising quality material in an extreme environment.

For the oxide ceramics, nitride ceramics in structural ceramics, below is their feature:

Alumina ceramics: the earliest and most widely used structural ceramics

Zirconia ceramics: high-performance structural ceramics, toughening is the key to preparation

Beryllium oxide ceramics: oxide ceramics with the highest thermal conductivity,

Silicon nitride ceramics: one of the materials with the best comprehensive properties in advanced ceramics

Aluminum nitride ceramics: ideal structural material for microelectronics industry circuit board and packaging

Boron nitride ceramics: soft ceramics in ceramic materials, good machinability

Ceramic Nozzle For Atomization Of Steel

Boron Nitride ceramic nozzles are widely used in the processing of atomization of steel. As its high strength, high melting point, high toughness, and outstanding thermal shock resistance, steel powder manufacturers use Boron Nitride material to make the atomizing nozzle. Also, BN material has no reaction or wetting with molten metals.

INNOVACERA developed a wide range of BN grades for the nozzles to meet the needs of different end users. When you send an inquiry, we’ll give you a suitable solution.

Ceramic Nozzle For Atomization Of Steel
Ceramic Nozzle For Atomization Of Steelatomization
Grade BN997 BN99 BN-SI BN-AL BN-SIC BN-ZR BN-ALN
Main Composition BN>99.7% BN>99% BN+AL+SI BN+ZR+AL BN+SIC BN+ZRO2 BN+ALN
Bonding Composition B2O3 B2O3 Boron oxide silicon Boron oxide aluminum Boron oxide aluminum B2O3 Boron oxide aluminum
Density (g/cm3) 1.6 2 2.2-2.3 2.25-2.35 2.4-2.5 2.8-2.9 2.8-2.9
Room Temperature Electric Resistivity (Ω·cm) >1014 >1014 >1013 >1013 >1012 >1012 >1013
Max Using Temperature (°C)
In Atmosphere
In Inactive Gas
In High Vacuum (Long Time)
900
2100
1800
900
2100
1800
900
1750
1750
900
1750
1750
900
1800
1800
900
1800
1800
900
1750
1750
Three-Point Bending Strength (MPA) 18 35 65 65 80 90 90
Compressive Strength (MPA) 45 85 145 145 175 220 220
Thermal Expansion Coefficient (20-1000°C)
(10-6/K)
1.5 1.8 2.0 2.0 2.8 3.5 2.8
Thermal Conductivity (W/m·k) 35 40 35 35 45 30 85

 

 

Beryllia Ceramic BeO Metallization

The thermal conductivity of BeO ceramics is very high, which is comparable to that of some metal materials; it also has the advantages of high-temperature resistance, high-pressure resistance, high strength, and low dielectric loss, which meets the requirements of power devices for insulation performance. However, BeO powder is a highly toxic substance, which can cause serious harm to the human body and the environment. This fatal shortcoming greatly limits the production and application of BeO ceramic substrates in the industrial field

Beryllia Ceramic BeO Metallization
Beryllia Ceramic BeO Metallization

 

The most commonly used metallization method for BeO ceramics is the molybdenum-manganese method. The method is to apply a paste-like mixture of pure metal powder (Mo, Mn) and metal oxides on the ceramic surface, and then heat it at a high temperature in a furnace to form a metal layer. Adding 10%~25%Mn to Mo powder is to improve the combination of metal coating and ceramics.

However, the molybdenum-manganese method also has certain limitations on the metallization of BeO ceramics. The thermal conductivity of BeO ceramics can reach more than 300W/(m•K), but the thermal conductivity of molybdenum is only 146W/(m•K). It is not conducive to the high heat dissipation characteristics of BeO ceramics. In order to improve this drawback, the tungsten-manganese method was developed on the basis of the molybdenum-manganese method. The thermal conductivity of metal tungsten is higher than that of metal molybdenum, and the electrical resistivity of tungsten is also lower than that of metal molybdenum. Therefore, the tungsten-manganese method can not only improve the heat dissipation efficiency of the overall structure but also help to improve the electrical conductivity of the metallization layer.