Application of vacuum heat treatment electric furnace for experiments in the ceramic industry

The vacuum heat treatment electric furnace used in experiments has a wide range of applications in the ceramic industry. Its core value lies in significantly improving the performance and preparation quality of ceramic materials through vacuum environment and precise temperature control technology. The specific application scenarios and advantages are as follows:

1. Core application scenarios
Ceramic sintering
Function: In a vacuum or controlled atmosphere (such as nitrogen or argon), ceramic powder is densified, pores are eliminated, and mechanical properties (such as strength and hardness) and thermal stability are improved by high-temperature heating.
case
When preparing highly transparent YAG: Nd ceramics, vacuum sintering at 1700-1800 ℃ can achieve a relative density of 99.98% and a grain size of 50 μ m, achieving laser output for the first time.
Aluminum oxide ceramics sintered under vacuum can avoid oxidation reactions, maintain surface smoothness, and are suitable for high-precision requirements such as electronic ceramic substrates.
ceramic to metal seal
Function: To achieve reliable connection between ceramics and metals in a vacuum environment, avoid interference from oxide layers, and improve sealing strength and airtightness.
case
In vacuum electronic devices, the sealing of ceramics and metals needs to be carried out under a vacuum degree of 10 ⁻³~10 ⁻⁵ Pa to ensure that the interface is free of oxidation impurities and meets the requirements for use in high vacuum environments.
Preparation of Ceramic Coatings
Function: By vacuum heat treatment (such as spray treatment), the density and adhesion of ceramic coatings are improved, enhancing wear resistance and corrosion resistance.
case
After coating the surface of aircraft engine turbine blades with zirconia ceramic coating, vacuum heat treatment can eliminate coating pores and improve high temperature resistance to over 1600 ℃.

2. Analysis of Technical Advantages
Vacuum environment suppresses oxidation and pollution
Principle: When the vacuum degree reaches 10 ⁻³~10 ⁻⁵ Pa, the oxygen partial pressure is extremely low, which can completely prevent ceramic materials from reacting with oxygen at high temperatures to generate oxide impurities.
effect:
Maintain material purity and improve electrical performance (such as the stability of the dielectric constant of insulating ceramics).
Reduce surface defects and improve the transmittance of optical ceramics (such as YAG ceramics with a transmittance of over 85%).
Accurate temperature control ensures consistent performance
Technology: Adopting PID controller, temperature control accuracy ± 1 ℃, programmable multi-stage heating curve (such as 30 stage program temperature control).
effect:
To avoid abnormal grain growth caused by temperature fluctuations and ensure the uniformity of the microstructure of ceramic materials.
Accurately control the phase transition process (such as the alpha beta phase transition of alumina ceramics) and optimize material properties.
Atmosphere control achieves diversified processes
Function: It can be filled with protective gases such as nitrogen and hydrogen, or mixed atmospheres (such as Ar+H ₂) to meet the processing needs of different ceramic materials.
case
Silicon nitride ceramics can be vacuum sintered under a nitrogen atmosphere, which can suppress decomposition reactions and improve material strength to over 1000 MPa.
Silicon carbide ceramics can be vacuum annealed in a hydrogen atmosphere to remove surface oxide layers and improve conductivity.

3. Equipment selection suggestions
temperature range
Ceramics such as alumina and zirconia: choose a high temperature furnace of 1600-1700 ℃ to ensure sufficient densification.
High melting point ceramics such as silicon nitride and silicon carbide require an ultra-high temperature furnace of 1800-2000 ℃ to meet the sintering temperature requirements.
Vacuum degree and atmosphere control
Preparation of high-purity ceramics: Prioritize using a 10 ⁻⁵ Pa high vacuum furnace to avoid trace oxidation.
Restoring atmosphere treatment: Select equipment with hydrogen/nitrogen gas inlet function, supporting atmosphere pressure regulation (such as 0.1~0.5MPa).
Furnace structure and dimensions
Small batch research and development: using a Φ 40~100mm tube furnace to save material costs.
Large sample processing: Choose a box furnace (such as a 300 × 300 × 300mm cavity), support multi-layer placement, and improve efficiency.

4. Industry application cases
aerospace field
Ceramic matrix composite (CMC) turbine blades: achieved dense bonding between silicon carbide fibers and matrix through vacuum heat treatment (1800 ℃/2h), with temperature resistance increased by 300 ℃ compared to metals.
In the field of electronic information
5G ceramic filter: High Q-value (>5000) ceramic media are prepared using vacuum sintering (1550 ℃/4h) to meet high-frequency communication requirements.
In the field of new energy
Solid state electrolyte ceramics (such as LLZO): Vacuum heat treatment (1200 ℃/10h) can eliminate the pores caused by lithium volatilization, and the ion conductivity can be increased to 10 ⁻ S/cm.