Low Pressure Vacuum Plasma Spraying For Aviation Turbine Blade Equipment

Zhengzhou Lijia's Vacuum Low Pressure Plasma Spraying System (PS-PVD) is an advanced surface treatment technology that significantly improves coating quality and process adaptability by plasma spraying in a low vacuum or controlled atmosphere environment. The following are its core features, advantages and system introduction:

 

 

I. The core characteristics of the system

1. Low vacuum environment
Operating in environments from 1.3×10³ Pa to near vacuum, it effectively reduces the contact between the plasma jet and the air and avoids oxidation of the coating material, especially for reactive metals (e.g. titanium, aluminum) and high-purity ceramic coatings.
2. Efficient particle heating and acceleration
The plasma jet beam is long and energy concentrated, the powder particles stay longer in the high temperature zone, melt more fully, and fly at a higher speed (supersonic), ensuring the compactness of the coating and the strength of the bond.
3. Substrate pretreatment and heating
The surface of the workpiece is sputtered (electrocleaned) by using a reverse transfer arc to remove oxide film and impurities, and at the same time, the substrate can be preheated to a higher temperature (e.g. above 800°C) to promote the metallurgical bonding of the coating to the substrate.
4. Environmental protection and safety
The closed vacuum chamber effectively isolates noise, dust and harmful gases, improves the operating environment, and is especially suitable for the spraying of toxic materials such as beryllium.

II. Technical advantages

1. Excellent coating performance
2. The coating has high bonding strength, low porosity, wear resistance, corrosion resistance and high temperature oxidation resistance, which are significantly better than atmospheric plasma spraying.
3. It can prepare high melting point materials (such as tungsten, molybdenum) and nanostructure coatings.
4. Process flexibility
5. Adapt to a variety of spray guns (such as F4, SG-100, etc.), support multi-angle, high-precision spraying of complex workpieces.
6. The spraying distance has little influence on the coating performance, and is suitable for large-size or special-shaped parts.
7. Cost optimization
8. High material utilization rate (reduce spatter), long maintenance cycle, reduce comprehensive use cost.

III.System composition and application

System composition

1. Vacuum chamber: equipped with vacuum extraction and inert gas filling system to support precise pressure control.
2. Plasma spray gun: such as the F4 spray gun, with a modular design, supports high powder feeding and efficient spraying.
3. Control system: The microprocessor monitors the current, gas flow and other parameters to ensure the stability and repeatability of the process.
4. Workpiece motion mechanism: robotic arm or rotating platform to achieve complex trajectory spraying.

Typical areas of application
Aerospace: thermal barrier coatings for turbine blades, anti-ablation coatings for rocket nozzles.
Energy: anti-corrosion coating for gas turbine components, protection of nuclear reactor components.
Medical: Biocompatible coatings on the surface of artificial joints (e.g. hydroxyapatite).
Semiconductors: Deposition of high-purity metal or ceramic thin films.
Zhengzhou Lijia vacuum low-pressure plasma spraying system has achieved a double breakthrough in coating performance and process efficiency through low vacuum environment, advanced spray gun technology and intelligent control, especially suitable for scenarios with demanding material performance and environmental requirements in the high-end manufacturing field. Its core strengths are coating quality, process flexibility and equipment reliability, providing customers with long-lasting surface solutions.

 

Aerospace: Components in this sector often operate in extreme environments and require demanding coating properties. For example, it can be used to spray thermal barrier coating on the surface of gas turbine components to reduce the temperature of the substrate and improve the high temperature resistance and service life of the components; It can also be used for the preparation of the coating of the rocket nozzle to enhance its wear resistance and ablation resistance.

Medical field: It is widely used in medical implants. The system allows implants to be sprayed with coatings such as titanium, hydroxyapatite or titanium/hydroxyapatite, which are biocompatible and promote the growth and adhesion of bone cells, as in the case of hip implants.

Automobile manufacturing field: It can be used to prepare thermal barrier coatings and functional coatings. For example, spraying coatings on the surface of engine components can improve their thermal insulation performance, reduce heat transfer, improve engine efficiency, and enhance the wear and corrosion resistance of components to extend their service life.

Petrochemical industry: equipment in this industry often faces problems such as corrosion and wear. The use of low-pressure vacuum plasma spraying system to prepare corrosion-resistant and wear-resistant coatings on the surface of pipelines, valves, pumps and other equipment can effectively improve the corrosion resistance and wear resistance of the equipment, reduce maintenance costs, and ensure the stable operation of the equipment.

Textile machinery field: coating can be applied on the surface of key components of textile machinery to improve the wear resistance, self-lubrication and other properties of components, reduce friction and wear between components, improve the operation efficiency and stability of machinery, and prolong the service life of machinery.

Product Operate Guide 

   

I. Preliminary preparations

1. Equipment inspection: ensure that the vacuum system has no leakage and can be evacuated normally; Check the wear of the electrode and nozzle of the plasma spray gun and replace them as needed; Confirm that the cooling channel and circuit connection of the water cable are normal, and the cooling water flow rate and pressure meet the standards; Ensure that the pressure and flow rate of argon and other gases in the gas supply system are stable and the purity is qualified.

2. Workpiece pretreatment: clean the oil, rust and other impurities on the surface of the workpiece, decide whether to preheat according to the size of the workpiece, if you need to preheat, use a forward transfer arc (workpiece anode, spray gun cathode) to quickly preheat.

3. Powder pretreatment: Choose powder of the same purity, dry and vacuum deoxygenation before powder feeding, so as to avoid damage to the coating quality.

Ⅱ. the spraying process

1. Create an environment: Vacuum and fill with inert gas to build a low-pressure protective atmosphere.

2. Electric cleaning process: After the reverse transfer arc (workpiece cathode, spray gun anode) or combined arc is turned on, the arc sputtering cleans the oxide film and dirt on the surface of the workpiece, promotes the formation of highly active surface, and helps the coating to combine with the matrix metallurgy.

3. Coating production: spraying according to the process setting parameters, focusing on monitoring:

- Plasma Jet: The characteristics are determined by the current, gas type, and flow rate, and are accurately monitored by a microprocessor to ensure accuracy and stability.

- Workpiece Movement: Complex parts rely on the mechanical system to control the spray gun and the workpiece manipulator to move the workpiece to ensure uniform coating.

- Powder Control Precise control of powder delivery speed, injection position and angle.

Ⅲ. Spraying aftercare

1. Cooling treatment: After spraying, the studio maintains a low-pressure inert atmosphere, and then fills the air when the workpiece is cooled below 100°C.

2. Quality verification: Check whether the coating is uniform and whether there are flaws, and check whether the coating performance is up to standard by means of hardness and bond strength testing.

Q1: Why is the price of the equipment so high?

A: The low-pressure vacuum plasma spraying system has a complex structure, including a vacuum system, a plasma spray gun, a gas supply system, an electrical control system and other precision parts, and the manufacturing process is demanding, and it also needs to be equipped with a high-quality monitoring and automation system to ensure the accurate control and stability of the spraying process. At the same time, R&D costs are also high, so the one-time investment in equipment is high.

Q2: What are the limitations of the machine on the size of the workpiece?

A: The size of the workpiece is limited by the size of the vacuum chamber, and it is necessary to ensure that the workpiece can be smoothly placed in the vacuum chamber for spraying operation, if the workpiece is too large, it cannot be sprayed with this system.

Q3: What are the process parameters that affect the quality of the coating?

A: There are mainly plasma jets (its characteristics depend on the current, gas type, gas flow), powder supply (powder purity, drying and deaeration treatment), matrix quality (whether it is cleaned and heated with transfer arc), the movement of the workpiece (to ensure that the surface of complex parts is uniformly coated), powder delivery and injection state.

Q4: Why is the bond strength of the coating sometimes not high?

A: It may be that the surface treatment of the substrate before spraying is improper, such as sandblasting on the thin substrate may bring impurities; Poor chemical corrosion treatment; Failure to clean or preheat the surface of the substrate with a transfer arc, or due to inappropriate substrate temperature during the spraying process.

Q5:What materials are suitable for spraying with the system?

A: It can spray a variety of metals, ceramics, cermets and other materials, but due to the reduced heating efficiency of low-pressure plasma jet and the low enthalpy value, it is relatively difficult to spray some high-melting point materials, and the feasibility needs to be carefully evaluated.

Q6:In which industries are it widely used?

A: It is used in aerospace, medical, automobile manufacturing, petrochemical, textile machinery and other industries. For example, in the aerospace field, it is used for the preparation of coatings for gas turbine components and rocket nozzles; In the medical field, it is used for implant surface coating treatment, etc.