How to choose the different types of phosphating process

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How to choose the different types of phosphating process

 According to the operating temperature, can be divided into high-temperature phosphating, medium-temperature phosphating, low-temperature phosphating.

1) low-temperature phosphating, at room temperature, long processing time, in addition to medium-temperature phosphating has been added to the composition, in order to accelerate the speed of phosphating, but also add fluoride, the advantage of low-temperature work, without heating. The solution is stable mud slag less, but the film corrosion resistance is poor, bonding, heat resistance is also poor, the processing time is long. This phosphate in the production of not much application, spray phosphating when applied.

2) medium-temperature phosphating 50 to 70 ℃, with Ma Zhifu salt, zinc dihydrogen phosphate and oxidizing agents (such as zinc nitrate, manganese nitrate, nickel nitrate) composed of phosphating solution, the film in addition to iron, manganese and other ferrous metals, but also interspersed with zinc, nickel. Film corrosion resistance, bonding and high-temperature phosphate film equivalent, stable solution, film speed, slag less than high-temperature phosphating. This process is applicable to a large area, in addition to the lower requirements for the hardness of the functional phosphate film, phosphating before painting the most applications. The disadvantage is that the composition of high-temperature phosphate is more complex, difficult to adjust.

3) high-temperature phosphate treatment temperature of 90 to 98 ℃, with Ma Zhifu salt and oxidizer (such as manganese nitrate) phosphate solution, phosphate film for iron, manganese, does not contain zinc. Film corrosion resistance, bonding, heat resistance, hardness are relatively high. The disadvantage is the long heating time, energy consumption, the amount of slag. Composition changes quickly, the solution is not stable. Phosphate crystallization coarse, thick film. This process is suitable for functional phosphate film, such as gears, automotive piston rings with friction reduction layer, lubrication phosphate layer between processing processes.

In summary, medium-temperature phosphating is the most promising process, in addition to the requirement that the phosphate film can not contain zinc components outside the parts, can be applied to most products in phosphate production, especially the use of phosphate filter so that the medium-temperature phosphate film more fine, inclusions and adsorption reduced, more suitable for pre-painting or some of the phosphate film requirements on a particularly fine product.

Most of the phosphating solutions sold on the market in recent years belong to this type of process. Certain phosphating solution in the oxidizer used organic oxide, organic oxide decomposition has a certain time, is the life of the organic oxide. In the life of the oxide to generate phosphate film, outside the life of the organic oxide, phosphate reaction basically stopped. This reduces the consumption of other components of the phosphate solution, the amount of slag is greatly reduced. And the analysis can be grasped by the oxidant content, the appropriate supplement for the situation.

According to the operating temperature, can be divided into high-temperature phosphating, medium-temperature phosphating, low-temperature phosphating.

1) low-temperature phosphating, at room temperature, long processing time, in addition to medium-temperature phosphating has been added to the composition, in order to accelerate the speed of phosphating, but also adding fluoride, the advantage of low-temperature work, without heating. The solution is stable mud slag less, but the film corrosion resistance is poor, bonding, heat resistance is also poor, the processing time is long. This kind of phosphating in production is not much, spray phosphating when applied.

2) medium-temperature phosphating 50 to 70 ℃, with Ma Zhifu salt, zinc dihydrogen phosphate and oxidizing agents (such as zinc nitrate, manganese nitrate, nickel nitrate) composed of phosphating solution, the film in addition to iron, manganese and other ferrous metals, but also interspersed with zinc, nickel. Film corrosion resistance, bonding and high-temperature phosphate film equivalent, stable solution, film speed, slag less than high-temperature phosphating. This process is applicable to a large area, in addition to the lower requirements for the hardness of the functional phosphate film, phosphating before painting the most applications. The disadvantage is that the composition of high-temperature phosphate is more complex, difficult to adjust.

3) high-temperature phosphate treatment temperature of 90 to 98 ℃, with Ma Zhifu salt and oxidizer (such as manganese nitrate) phosphate solution, phosphate film for iron, manganese, does not contain zinc. Film corrosion resistance, bonding, heat resistance, hardness are relatively high. The disadvantage is the long heating time, energy consumption, the amount of slag. Composition changes quickly, the solution is not stable. Phosphate crystallization coarse, thick film. This process is suitable for functional phosphate film, such as gears, automotive piston rings with friction reduction layer, lubrication phosphate layer between processing processes.

In summary, medium-temperature phosphating is the most promising process, in addition to the requirement that the phosphate film can not contain zinc components outside the parts, can be applied to most products in phosphate production, especially the use of phosphate filter so that the medium-temperature phosphate film more fine, inclusions and adsorption reduced, more suitable for pre-painting or some of the phosphate film requirements on a particularly fine product.

Most of the phosphating solutions sold on the market in recent years belong to this type of process. Certain phosphating solution in the oxidizer used organic oxide, organic oxide decomposition has a certain time, is the life of the organic oxide. In the life of the oxide to generate phosphate film, outside the life of the organic oxide, phosphate reaction basically stopped. This reduces the consumption of other components of the phosphate solution, the amount of slag is greatly reduced. And the analysis can be grasped by the oxidant content, the appropriate supplement for the situation.

According to the operating temperature, can be divided into high-temperature phosphating, medium-temperature phosphating, low-temperature phosphating.

1) low-temperature phosphating, at room temperature, long processing time, in addition to medium-temperature phosphating has been added to the composition, in order to accelerate the speed of phosphating, but also adding fluoride, the advantage of low-temperature work, without heating. The solution is stable mud slag less, but the film corrosion resistance is poor, bonding, heat resistance is also poor, the processing time is long. This kind of phosphating in production is not much, spray phosphating when applied.

2) medium-temperature phosphating 50 to 70 ℃, with Ma Zhifu salt, zinc dihydrogen phosphate and oxidizing agents (such as zinc nitrate, manganese nitrate, nickel nitrate) composed of phosphating solution, the film in addition to iron, manganese and other ferrous metals, but also interspersed with zinc, nickel. Film corrosion resistance, bonding and high-temperature phosphate film equivalent, stable solution, film speed, slag less than high-temperature phosphating. This process is applicable to a large area, in addition to the lower requirements for the hardness of the functional phosphate film, phosphating before painting the most applications. The disadvantage is that the composition of high-temperature phosphate is more complex, difficult to adjust.

3) high-temperature phosphate treatment temperature of 90 to 98 ℃, with Ma Zhifu salt and oxidizer (such as manganese nitrate) phosphate solution, phosphate film for iron, manganese, does not contain zinc. Film corrosion resistance, bonding, heat resistance, hardness are relatively high. The disadvantage is the long heating time, energy consumption, the amount of slag. Composition changes quickly, the solution is not stable. Phosphate crystallization coarse, thick film. This process is suitable for functional phosphate film, such as gears, automotive piston rings with friction reduction layer, lubrication phosphate layer between processing processes.

In summary, medium-temperature phosphating is the most promising process, in addition to the requirement that the phosphate film can not contain zinc components outside the parts, can be applied to most products in phosphate production, especially the use of phosphate filter so that the medium-temperature phosphate film more fine, inclusions and adsorption reduced, more suitable for pre-painting or some of the phosphate film requirements on a particularly fine product.

Most of the phosphating solutions sold on the market in recent years belong to this type of process. Certain phosphating solution in the oxidizer used organic oxide, organic oxide decomposition has a certain time, is the life of the organic oxide. In the life of the oxide to generate phosphate film, outside the life of the organic oxide, phosphate reaction basically stopped. This reduces the consumption of other components of the phosphate solution, the amount of slag is greatly reduced. And through the analysis can grasp the content of the oxidizer, the appropriate supplement for the situation.