What are the characteristics of spiral axis sprayed alumina ceramic coating

Source：www.marydick.cn Release date： 2025年06月09日

Information summary：Spiral axis spraying alumina ceramic coating is a process of attaching high hardness and wear-resistant alumina ceramic materials to the surface of a metal substrate through thermal spraying techniques such as plasma spraying, supersonic flame spraying, etc. This coating endows the spiral shaft with unique performance advantages, which are mainly reflected in the following aspects: 1、 High hardne

Spiral axis spraying alumina ceramic coating is a process of attaching high hardness and wear-resistant alumina ceramic materials to the surface of a metal substrate through thermal spraying techniques such as plasma spraying, supersonic flame spraying, etc. This coating endows the spiral shaft with unique performance advantages, which are mainly reflected in the following aspects:
1、 High hardness and wear resistance
1. Significant improvement in hardness: The hardness of aluminum oxide ceramic (Al ? O ∝) coating can reach HV 1000~1500 (approximately equivalent to HRC 70~80), which is much higher than that of ordinary metal materials (such as stainless steel with a hardness of about HV 200~300).
2. Excellent wear resistance: It can resist long-term friction between the spiral shaft and granular materials (such as ore, sand, and powder) during transportation and mixing, extending its service life, especially suitable for strong wear conditions in mining, building materials, chemical industry, etc.
3. Impact resistance and peeling: By optimizing the bonding process between the coating and the substrate (such as sandblasting roughening and transition layer design), the risk of coating cracking or peeling can be reduced, balancing hardness and toughness.
2、 Corrosion resistance and chemical stability
1. Acid and alkali corrosion resistance: Alumina ceramics have inert chemical properties and can resist the erosion of various acids (such as sulfuric acid, hydrochloric acid), alkalis (such as sodium hydroxide), and salt solutions. They are suitable for corrosive environments such as chemical engineering and sewage treatment.
2. Strong oxidation resistance: In high temperature environments (such as ≤ 800 ℃), the coating is not easily reactive with oxygen, which can protect the spiral axis substrate from oxidation corrosion.
3、 High temperature resistance and thermal insulation performance
1. High temperature stability: The melting point of alumina ceramics is as high as 2054 ℃, and the coating can work for a long time at 600-1000 ℃ without softening or deformation, making it suitable for conveying high-temperature materials such as sintered ore and hot sand.
2. Thermal insulation effect: Ceramic coatings have low thermal conductivity (about 1-3 W/m · K, while metal substrates usually have 40-100 W/m · K), which can reduce the heat conduction between the spiral shaft and high-temperature materials, and lower the risk of thermal damage to the substrate.
4、 Surface Characteristics and Fluid Optimization
Low surface roughness: Through precision grinding or polishing processes, the surface roughness of the coating can be controlled within Ra 0.2~1.6 μ m, reducing material adhesion (such as viscous powders and wet materials), improving conveying efficiency, and avoiding material retention and deterioration.
Hydrophobicity and anti adhesion: Ceramic surfaces have low polarity and weak adsorption for liquids such as water and oil, making them suitable for transporting damp or viscous materials (such as food and pharmaceutical raw materials) and easy to clean and maintain.
5、 Bonding performance between coating and substrate
High bonding strength: When using processes such as plasma spraying, the bonding strength between the coating and the substrate can reach 30-50 MPa (higher for supersonic flame spraying), ensuring that the coating is not easily peeled off under alternating loads.
Transition layer design: Some processes will first spray a metal bottom layer (such as nickel chromium alloy), and then stack a ceramic layer to alleviate the difference in thermal expansion coefficient through a "metal ceramic" gradient structure (the difference in thermal expansion coefficient between ceramics and metals is about 1-2 times), reducing internal stress.

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