Technical service support

Zindn Shield has a group of technical personnel with rich concepts and practical experience returning from overseas, and cooperates with many domestic universities and research institutes to build an academic and application cooperation platform. Technical level and strength are at the forefront of the industry.

• In the case of considering the cost during the construction process, the cold sprayed zinc coating often fails to reach the design thickness, or even less than half of the design thickness. The missing thickness can only be supplemented by a relatively low-cost sealing agent, which causes the sealing layer to exceed the design thickness.

  The thickness of the cold sprayed zinc itself is insufficient, and the excessive thickness of the sealant leads to serious solvent infiltration of the sealant, which makes the fusion layer become a serious underbite, which destroys the internal structure of the cold sprayed zinc and eventually cracks.

  A: According to the test and observation and comparison test of the intact surface and damaged surface on site, we found that the reasonable coating thickness of cold sprayed zinc in the composite coating must be maintained between 60-120μm, and the thickness of the sealing layer should not be higher than 200μm. The resulting fusion layer is between 15-25 μm, which is the ideal effect in the coating system.

  Suggestions and treatment schemes: The thickness of the coating needs to be rationalized in the early stage of the design; the thickness is controlled, and the construction process pays special attention to the use of cold-spray zinc sealant. A mist spray and subsequent wet compaction are used to avoid the sealant. The film thickness is too thick.

  

• In the coating process, due to gravity and structural problems, the triangular area and the T-shaped area overlapped or accumulated too much during the coating process. This situation is often accompanied by the factors that the paint cannot be dried or the drying time is too long. In the subsequent coating, a similar situation occurs in the coating process of each layer, resulting in the retention of the solvent.

  A: Solvent retention is a coating problem with a high degree of potential danger. Solvent retention will cause serious biting or bottoming. If the solvent evaporates slowly at a low temperature in the later stage, emptying will occur, affecting the service life of the components. If the component with solvent retention problems in the later stage will evaporate quickly to the painted surface under high temperature, it will show cracking in the later stage.Suggestions and treatment plan: strengthen inspection and inspection during construction; equip relevant painters with high-quality brushes, find and handle in time.

  

• The component needs to be welded to the board unit during the processing process. After the component is manufactured, some projects will have stress relief steps, but in reality the stress cannot be completely eliminated. There is residual stress in the weld area. So what forces are involved in coating in the weld area?

  A: (1) Residual stress of the weld or structure; (2) Surface tension during the film formation process of the coating; (3) The coating is subjected to gravity. Especially in the first two items, the stress cannot be eliminated, and the surface tension is too large, resulting in limited paint that cannot completely fill the weld area, leaving room for solvent retention.

  Suggestions and treatment schemes: (1) In this area, the importance of pre-coating work is particularly important. Pre-coating is the best way to eliminate hidden dangers; (2) Improvement of coating methods, welds and narrow areas of welds Use covering coating (appropriately covering the area when painting the surrounding area. Do not intentionally or specifically paint the area) to achieve the effect of controlling the thickness.

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