Vacuum Sintering Furnace

I. Core Principle: Vacuum Environment + Precise Temperature Control to Address Traditional Sintering Pain Points

1. Oxidation/Pollution Prevention: The vacuum environment isolates oxygen, avoiding high-temperature oxidation of metals (e.g., titanium alloys, tungsten-molybdenum alloys) while reducing chemical reactions between gaseous impurities (e.g., H₂O, CO₂) and materials;
2. Degassing and Purification: Adsorbed gases (e.g., hydrogen, nitrogen) inside materials volatilize at high temperatures and are discharged by the vacuum pump, reducing the porosity of materials;
3. Precise Densification: Heat transfer in a vacuum environment is more uniform (mainly through radiant heat transfer). Combined with a temperature control accuracy of ±1℃, it ensures uniform growth of material microcrystals and avoids local over-sintering or incomplete sintering.

II. Core Structure: Composed of 5 Systems, All Indispensable

III. Main Classifications: Divided by Heating Method/Application Scenario

1. Classified by Heating Element
   • Graphite-heated Type: The heating element is high-purity graphite, which is resistant to high temperatures (up to 2200℃) and has uniform heat conduction. It is suitable for sintering cemented carbides (e.g., tungsten-cobalt alloys) and graphite materials;
   • Metal-heated Type: The heating element is molybdenum wire or tungsten wire, with a higher vacuum level (up to 10⁻⁵Pa). It is suitable for sintering active metals such as titanium alloys and superalloys;
   • Ceramic-heated Type: The heating element is a SiC rod or MoSi₂ rod, suitable for sintering ceramic materials such as alumina and silicon nitride to avoid metal contamination.
2. Classified by Application Scenario
   • Special Furnace for Cemented Carbides: Used for sintering cemented carbides (e.g., WC-Co alloys) for cutting tools and molds, and needs to be combined with a "dewaxing" process (to remove the forming agent in materials);
   • Special Furnace for Semiconductors: Used for sintering silicon wafers and silicon carbide (SiC) wafers, requiring extremely high vacuum levels (10⁻⁶Pa) and cleanliness to avoid impurities affecting semiconductor performance;
   • Special Furnace for Powder Metallurgy: Used for sintering metal powders such as iron powder and copper powder, and can realize integrated "sintering + hot pressing" (further improving density through pressure application).

IV. Key Application Fields: The "Invisible Cornerstone" of High-end Manufacturing

• Aerospace: Preparation of titanium alloy engine blades and superalloy combustion chambers (which need to withstand high temperatures above 1000℃ without oxidation defects);
• Semiconductors: "Sintering bonding" of SiC power devices (sintering chips and substrates with metal solder to improve heat dissipation efficiency);
• New Energy: Sintering of cathode materials (e.g., sulfide electrolytes) for solid-state batteries (the vacuum environment prevents electrolytes from reacting with air);
• Cemented Carbides: Sintering of WC-Co alloys for cutting tools and mining drill bits (vacuum degassing can reduce the risk of tool chipping);
• Medical Devices: Sintering of artificial joints (titanium alloy/ceramic materials) (requiring extremely high density to prevent body fluid infiltration and corrosion).

V. Selection and Usage Precautions

1. Core Indicators for Selection
   • Maximum Temperature: Selected based on the sintering temperature of materials (e.g., over 1600℃ for ceramics, 800~1200℃ for metal powders);
   • Vacuum Level: 10⁻⁴Pa or higher for active metals (e.g., titanium), and 10⁻²Pa is sufficient for ordinary metal powders;
   • Furnace Chamber Size: Matches production volume (small laboratory furnace chambers <50L, large industrial furnace chambers up to 500L or more);
   • Temperature Control Accuracy: ±0.5℃ for high-end applications (e.g., semiconductors), and ±1℃ for ordinary powder metallurgy.
2. Key Precautions for Usage
   • Vacuum Level Inspection: Check the airtightness of the furnace body (e.g., using a helium mass spectrometer leak detector) before each startup to avoid material oxidation caused by air leakage;
   • Heating Element Maintenance: Graphite heating elements should be prevented from contacting oxygen (easily oxidized and burned at high temperatures), and metal heating elements should be protected from "material splashing" (molten materials sticking to elements causing short circuits);
   • Cooling Protection: After sintering, wait until the furnace temperature drops below 200℃ before breaking the vacuum (introducing air) to avoid instantaneous oxidation of high-temperature materials when exposed to air.

VI. Industry Trends: Intelligence and Enlargement

1. Intelligence: Introduce AI temperature control algorithms to automatically optimize sintering curves (e.g., adjusting heating rate according to material batches); integrate the Internet of Things to monitor furnace pressure and temperature in real time, enabling remote operation and maintenance;
2. Enlargement and Integration: Develop large-scale equipment with furnace chamber sizes exceeding 1m for wind power bearings and large aerospace components; meanwhile, integrate the entire process of "dewaxing - sintering - hot pressing - cooling" to reduce pollution caused by material transfer between processes.