Can a vacuum sintering furnace sinter metals?

Vacuum sintering furnaces are capable of sintering metal materials and have wide applications in the field of metal processing. It effectively solves the problems of oxidation, volatilization, and component segregation of metals during high-temperature sintering by creating low oxygen or oxygen free environments, significantly improving material properties. The following analysis is conducted from three dimensions: technical principles, application scenarios, and industry practices:

1. Technical principle: How to optimize the metal sintering process in vacuum sintering
Inhibit oxidation and decarbonization
Metals are prone to react with oxygen at high temperatures to form oxides (such as iron oxidation), or react with carbon to cause decarburization (such as a decrease in surface hardness of steel). The vacuum sintering furnace isolates oxygen and avoids oxidation and decarburization by vacuuming to a low-pressure environment of 10 ⁻ ² to 10 ⁻ ³ Pa. For example:
Stainless steel sintering: When sintered in air, a chromium oxide layer forms on the surface, reducing corrosion resistance; Vacuum sintering can maintain surface smoothness and improve corrosion resistance.
High speed steel cutting tools: Vacuum sintering can reduce carbide decomposition, maintain tool hardness and wear resistance.
Reduce volatility and control composition
If metals contain low melting point or volatile elements (such as zinc in copper based alloys and boron in nickel based alloys), they are prone to volatilization at high temperatures, leading to component segregation. A vacuum environment can reduce the volatilization rate and maintain the uniformity of the components. For example:
Copper based powder metallurgy parts: Vacuum sintering can reduce zinc volatilization, increase part density, and enhance tensile strength.
Nickel based high-temperature alloys: Vacuum sintering can control the volatilization of boron elements, avoid grain boundary embrittlement, and improve the durability strength of the material at 1000 ℃.
Promote densification and uniformity
Under vacuum conditions, gas escape between metal powder particles is more thorough, reducing porosity and increasing density. For example:
Titanium alloy: After vacuum sintering, it has high density, low porosity, and improved fatigue life compared to air sintering.
Aluminum alloy: Vacuum sintering can eliminate pores, improve tensile strength, and increase elongation.
Accurately control the atmosphere and pressure
Partial vacuum sintering furnaces can be filled with inert gases (such as argon) or reducing gases (such as hydrogen) to further optimize the sintering process. For example:
Active metals (such as titanium and zirconium): should be sintered under argon protection to avoid reaction with nitrogen or hydrogen; The vacuum furnace can accurately control the gas partial pressure to ensure material stability.
Reduction atmosphere sintering: For example, copper powder can be sintered in a hydrogen atmosphere to remove surface oxides, enhance sintering activity, and increase part density.

2. Application scenario: The core use of vacuum sintering furnace in metal processing
Powder metallurgy parts
Typical materials: iron-based, copper based, stainless steel, hard alloy (such as WC Co).
Sintering requirements: High density, high strength, and wear resistance are required.
Advantages of vacuum sintering:
Iron based gears: After vacuum sintering, the density is higher, the tensile strength is stronger, and the wear resistance is improved.
Hard alloy cutting tools: Vacuum sintering can reduce cobalt volatilization, achieving the optimal balance between hardness and toughness.
High temperature alloys and special metals
Typical materials: nickel based high-temperature alloys (such as Inconel 718), titanium alloys (such as Ti-6Al-4V), tungsten alloys.
Sintering requirements: High temperature resistance, corrosion resistance, and fatigue resistance are required.
Advantages of vacuum sintering:
Nickel based turbine disc: After vacuum sintering, the grain size is fine and uniform, and the endurance strength at 650 ℃ is higher than that of air sintering.
Tungsten alloy armor piercing core: Vacuum sintering can eliminate pores, increase density, and improve armor piercing performance.
Precious Metals and Precision Parts
Typical materials: gold, silver, platinum, palladium, and their alloys.
Sintering requirements: High purity, low oxidation, and precise size control are required.
Advantages of vacuum sintering:
Gold jewelry: Vacuum sintering can avoid surface oxidation, maintain luster, reduce welding marks, and improve yield.
Platinum based catalyst: Vacuum sintering can control the pore structure, resulting in a higher specific surface area and improved catalytic activity.
Metal based composite materials
Typical materials: Aluminum based silicon carbide (Al SiC), magnesium based aluminum oxide (Mg Al ₂ O3).
Sintering requirements: It is necessary to enhance the uniform distribution of phases and high interfacial bonding strength.
Advantages of vacuum sintering:
Al SiC composite material: Vacuum sintering can reduce interfacial reactions and increase thermal conductivity, which is slightly higher than air sintering.
Mg Al ₂ O ∝ composite material: Vacuum sintering can eliminate pores, resulting in greater bending strength and an improvement compared to castings.

3. Industry Practice: A Typical Case of Vacuum Sintering Furnace in Metal Production
Aerospace field
Case: A certain enterprise uses a vacuum sintering furnace to prepare titanium alloy aviation fasteners. By precisely controlling the sintering temperature (1200-1300 ℃) and argon partial pressure, the density of the parts is increased, the tensile strength is high, and the fatigue life is improved compared to air sintering. It has been successfully applied to the C919 aircraft.
Automotive industry field
Case: A certain automotive parts manufacturer uses a vacuum sintering furnace to produce powder metallurgy transmission gears. Through a multi-stage pressure control system, the density of the parts is increased, noise is reduced, and the service life is extended.
In the field of electronics industry
Case: A certain electronic component enterprise uses a vacuum sintering furnace to prepare silver based contacts. Through dynamic vacuum compensation technology, the oxidation rate is reduced, the contact resistance is reduced, and the product yield is improved.
medical field
Case: A medical device company used a vacuum sintering furnace to prepare cobalt chromium alloy artificial joints. By precisely controlling the sintering atmosphere (hydrogen reduction), the addition of carbon impurities was reduced, resulting in improved corrosion resistance of the material and reduced looseness rate after clinical application.