Surface alloying is an effective method for enhancing the corrosion resistance, hydrogen embrittlement resistance and wear resistance of titanium plates. Although titanium and its alloys have excellent corrosion resistance and specific strength, their surface's oxidation or hydrogen penetration is likely to occur in high-temperature or hydrogen-containing environments. It will result in performance degradation. By forming an alloying modification layer on the surface of the titanium plate, the interface properties can be significantly improved. Compared with the oxide coating coated with palladium, the surface alloying layer has a metallurgical bond with the substrate, featuring strong bonding force, wear resistance, and corrosion resistance, and is currently an important development direction for the surface treatment of titanium materials.
Aluminum diffusion coating process
Applying the aluminum diffusion coating process on the surface of the product can effectively reduce the hydrogen absorption tendency of titanium and form a dense hydrogen diffusion barrier layer.
Aluminum diffusion coating formula and temperature conditions
After process verification, the optimal aluminum diffusion conditions are as follows: mix 88% alumina, 4% aluminum fluoride, and 8% aluminum powder evenly, and then coat them on the surface of the titanium workpiece. The heating temperature is controlled at 810℃. At this temperature, aluminum fluoride acts as an activator, promoting the diffusion of aluminum atoms into the titanium matrix.
Coating thickness and structure
The thickness and phase composition of the aluminum diffusion coating mainly depend on the holding time. Using the package diffusion method for short-term diffusion treatment can obtain a thin coating of approximately 2 millimeters in thickness. This coating has good adhesion to the substrate and does not have adverse effects on the mechanical properties of the titanium substrate. The coating is mainly composed of the titanium oxide phase, forming an effective hydrogen diffusion barrier layer, significantly reducing the hydrogen absorption risk of the titanium material in acidic or high-temperature humid environments.
Palladium plating layer diffusion alloying process
After palladium plating on the titanium plate, heating can cause the palladium plating layer to diffuse towards the surface layer of the titanium substrate, forming a titanium-palladium alloying layer, thereby enhancing the corrosion resistance of the material in reducing acid media.
Heating diffusion method
Place the palladium-plated titanium plate in an appropriate atmosphere and heat it. By controlling the temperature and time, palladium atoms can diffuse inward, forming a titanium-palladium solid solution or intermetallic compound on the surface layer. This significantly improves the surface electrode potential and reduces the corrosion tendency.
Laser surface remelting method
Both the heating diffusion method and the laser surface remelting method are feasible in principle. Among them, the laser remelting technology has greater process flexibility: using a high-energy laser beam to irradiate the titanium surface, causing the pre-vacuum-deposited 150-micron-thick palladium plating film to rapidly melt and mix and diffuse with the underlying titanium substrate, forming a uniformly composed palladium alloy modified layer during the subsequent rapid solidification process. This process has a narrow heat affected zone and small deformation, and can precisely control the alloying depth and microstructure.
The vacuum infiltration method for aluminum infiltration and palladium plating combined with laser diffusion alloying are two effective surface modification techniques for titanium plates. The former focuses on anti-hydrogen embrittlement performance, with simple process and low cost; the latter aims to enhance corrosion resistance, especially suitable for strong corrosive medium environments. In practical applications, an appropriate solution can be selected based on the service conditions of the workpiece, or the two processes can be combined to achieve composite performance. With the continuous maturity of laser processing and powder embedding technology, the surface alloying process for titanium plates is gradually evolving towards precision and efficiency, providing a reliable guarantee for the in-depth application of titanium materials in fields such as chemical industry, marine, and nuclear industries.
Baoji Yibaite New Materials Technology Co., Ltd. - the best supplier of high-quality titanium plates in China.
Welcome to your price consultation.