What is the adsorption rate of supersonic spraying?

Powder characteristics and parameters of supersonic spraying process:

(1) Powder characteristics:

At present, powder suppliers provide various types of carbon (chemical powders, powder characteristics often vary greatly due to different powder manufacturing methods. Powder characteristics include powder particle size distribution.)

(2) Oxygen gas flow rate and ratio

The flow temperature and characteristics of spraying depend on the oxygen flow rate and mixing ratio. When spraying, the flow rates of oxygen and gas should be determined according to the requirements of the equipment to ensure that the smoke flow of the spray gun reaches the designed power level. In the actual production process, there are many factors that can cause fluctuations in the oxygen ratio, and the oxygen ratio is very important for determining the coating structure.

In theory, complete combustion of propane requires a 5:1 ratio of oxygen to propane. (C3H8+502=4h20+3CQ2) This combustion ratio produces a neutral flame (i.e. all oxygen and gas molecules are exhausted during combustion). If the gas ratio decreases, oxygen molecules that are not depleted in the flame will be produced. The "oxidizing" atmosphere causes the molten powder to undergo particle peroxidation, increasing the content of oxides in the coating. Excessive gas in the mixture will generate low-temperature oxygen deficient flames, increase unmelted particles and pores in the coating, and decrease the oxide content. In fact, neutral flames do not exist. At high temperatures, the combustion process is not completely reversible. The reactants and reaction products coexist in thermal equilibrium and chemical equilibrium.

(3) Spray distance:

The supersonic spraying system, when the powder particles are 100mm away from the nozzle outlet, the particle temperature gradually decreases with the increase of spraying distance, reaching high temperature between 10~230, and the temperature of mm particles decreases by about 6 within the range. At O ℃, its fertility does not decrease significantly, and particles can still maintain high temperatures of around 1775 ℃; And the particle velocity is gradually accelerating between approximately 1900mm from the nozzle outlet and 190-200 mm from the nozzle outlet. At a high-speed mm spray distance of over 170-230 mm (reaching around 580m/s), the particle velocity remains at around 58. Om/s or above. Considering the adverse effects of high-temperature flame flow on substrate heat transfer, the spray distance should be increased as much as possible. Therefore, for the ZB-270 supersonic flame spraying system, the suitable spray distance should be 10. 230mm。

Compared with other spray painting techniques, the adjustable range of spray distance is relatively large, thanks to the high velocity of particles. A larger adjustable spray distance range is very advantageous for practical production, as suitable spray distances can be selected according to the shape, size, coating thickness, and other requirements of the workpiece to obtain coatings with good comprehensive performance.

(4) Powder delivery quantity:

For any thermal spraying process, powder feeding rate is an important parameter that affects coating performance. Under specific spraying process conditions, a certain powder has a suitable range of powder feeding.