To improve the bonding strength between the antioxidant coating and the substrate material, the following aspects can be taken into consideration:
In terms of substrate surface pretreatment
Cleaning treatment:
Thoroughly remove impurities such as oil stains, dust, rust, etc. from the surface of the substrate. For example, for metal substrates, organic solvents (such as acetone, alcohol, etc.) can be used to wipe and remove surface oil stains; For metals with rust layers, rust can be removed by pickling, polishing, and other methods to make the substrate surface appear clean, so that the coating can better contact and adhere to it, enhancing the bonding strength.
For ceramic substrates, it is also necessary to remove impurities such as dust and mold release agent residues on the surface. Ultrasonic cleaning can be used to ensure a clean and tidy surface, which is conducive to the subsequent coating and bonding.
Surface roughening treatment:
Roughen the surface of the substrate through methods such as sandblasting and mechanical polishing. For example, sanding the surface of metal components with sandpaper or using sandblasting machines to spray abrasives such as quartz sand can increase the specific surface area of the substrate. This way, the coating can be embedded into these rough surface structures during coating, forming a "mechanical interlocking" effect and significantly improving the bonding strength.
For some hard substrate materials, laser etching and other methods can also be used to manufacture micro rough structures, providing more adhesion sites for the coating and strengthening the bond between the two without affecting the overall performance of the substrate.
Chemical activation treatment:
Adopt corresponding chemical treatment methods for different matrix materials to activate the surface. For example, for aluminum substrates, alkaline solution can be used for treatment to form an active layer of alumina hydrate on their surface, which can react chemically with subsequent coatings to enhance bonding strength.
For steel substrates, phosphating treatment can be used to generate a layer of phosphating film on the surface, which can better bond with certain components in the coating and improve the firmness of the connection between the coating and the substrate.
In terms of coating preparation process
Optimize the thermal spraying process (taking the preparation of coatings by thermal spraying as an example):
Control the spraying parameters, such as spraying distance, spraying speed, spraying angle, etc. The appropriate spraying distance can ensure that the coating particles have appropriate kinetic energy and temperature when they reach the substrate, which is conducive to their full bonding and uniform deposition with the substrate. Generally, the optimal spraying distance corresponding to different spraying materials and substrates varies, and needs to be accurately determined through experiments; The spraying speed should be moderate to avoid particles that are too fast or too slow affecting the bonding effect; The spraying angle should be kept perpendicular to the surface of the substrate as much as possible to reduce problems such as coating looseness and poor bonding caused by oblique spraying.
Choosing appropriate heat sources, such as plasma spraying, supersonic flame spraying, etc., results in different coating qualities and bonding strengths with the substrate. For example, the coating particles produced by supersonic flame spraying have high velocity and suitable temperature, which can make the coating bond more tightly with the substrate, making it more suitable for the preparation of high-performance anti-oxidation coatings.
Appropriate sol gel process is adopted (taking the preparation of coating by sol gel method as an example):
Strictly control the preparation parameters of the sol, including solution concentration, pH value, reaction temperature, and time. For example, an appropriate pH value can ensure the stability and uniformity of the sol, which in turn affects the quality of the final coating and its bonding with the substrate. It is crucial to find the optimal pH range through repeated experiments; Control the reaction temperature and time well to ensure that the generated sol has ideal structure and properties, which is conducive to the formation of a firmly bonded coating on the substrate in the future.
During the drying and sintering of gel, appropriate heating rate and drying conditions shall be adopted. Slow and reasonable heating rate can avoid cracks and other defects in the gel caused by too fast heating, so that the coating can better match with the substrate and improve the bonding strength; Appropriate drying conditions (such as vacuum drying, constant temperature drying and other different methods and corresponding parameters) can ensure a more stable transformation process from gel to coating, and improve the bonding effect of coating and substrate.
Application of intermediate transition layer
Choose the appropriate transition layer material:
For metal matrix and ceramic coating systems, intermetallic compounds (such as TiAl, NiAl, etc.) can be used as transition layer materials. These intermetallic compounds have good chemical compatibility and bonding with the metal substrate on the one hand, and can be connected to ceramic coatings through chemical bonding and other means, effectively compensating for the significant differences in physical and chemical properties between metals and ceramics, and enhancing the overall bonding strength.
When the substrate is a ceramic material and the coating is a different ceramic or metal coating, oxides with good adhesion and chemical adaptability (such as titanium dioxide, zirconium dioxide, etc.) can be used as transition layer materials, which can play a "bridge" role between the substrate and the target coating, improving the bonding between the two.
Control the thickness and quality of the transition layer:
The thickness of the transition layer should be moderate. If it is too thin, it may not have a good transition connection effect. If it is too thick, it is easy to cause unstable performance, cracking and other problems, which will affect the bonding effect. The optimal thickness range is generally determined through experiments, and the appropriate thickness varies for different substrates and coating systems.
To ensure the quality of the transition layer, strict control of process parameters is necessary during the preparation process to ensure that the transition layer is uniform, dense, and free of defects such as pores and cracks, in order to better enhance its bonding strength.
Regarding post-treatment of coatings
Heat treatment:
Perform appropriate heat treatment on the coated material, and select suitable heat treatment parameters such as temperature, time, and atmosphere based on the material characteristics of the substrate and coating. For example, for some metal based antioxidant coatings, high-temperature heat treatment under a certain inert atmosphere can promote element diffusion between the coating and the substrate, forming a tighter chemical bond between the two, thereby improving the bonding strength; For ceramic coatings, appropriate heat treatment can eliminate internal stresses in the coating and make it adhere more tightly to the substrate.
Adopting a graded heat treatment method, which gradually follows a certain heating, insulation, and cooling program, helps to more finely regulate the bonding state between the coating and the substrate, reducing problems such as coating peeling and poor bonding caused by rapid temperature changes.
Surface modification:
Using techniques such as ion implantation and laser surface treatment to modify the coated surface. For example, by injecting specific ions (such as nitrogen ions, boron ions, etc.) into the surface of the coating through ion implantation technology, the chemical composition and structure of the coating surface can be changed, the activity of the coating surface can be enhanced, and the bonding between it and the substrate can be more firm; Laser surface treatment can perform micro melting, recrystallization and other operations on the coating surface, improve the microstructure of the coating, and thereby enhance the bonding strength with the substrate.

Room termperature curing polysilazane, pls check IOTA 9150, IOTA 9150K.    
High termperature curing polysilazane, pls check IOTA 9108, IOTA 9118.