1 Heterogeneous impurities, which are foreign objects that fall into the powder during the preparation or treatment of the powder, such as infusions, sandals, sawdust or hair. The main reason for the generation of heterogeneous impurities is mainly from the following;
A foreign body falling off in the production system;
B When the finished product is covered, Ali will fall into the foreign body;
C Take precautions against improper storage of foreign objects.
2 Unity, unity is also called agglomeration. He is a phenomenon in which the powder is stored or transported due to poor airtightness or poor management of the package, and the powder is exposed to the tide and reunion. The main reason for aluminum powder is usually as follows.
A package is not airtight, powder moisture absorption
B The package is wet and infiltrated into the powder, such as rain or moisture in the drum.
C improper storage and transportation, such as the rainy days do not close the warehouse door, do not pay attention to ventilation, there is no proper precautionary measures for leaking in the warehouse, rain and snow transportation vehicles are not Peng.
The corresponding preventive measures can be taken against the cause.
Two physical defects
1 Strength exceeds the standard. Exceeding the standard is mainly because the particle size distribution or average particle size of the powder does not meet the product standard or customer requirements.
2 The loose density is low. Loose density defects mainly refer to the loose density below the standard.
3 The low adhesion rate, also called the floating percentage, is an important part of the standard of the floatability of the coating aluminum powder. The high or low standard reflects the quality of the product to some extent.
4 Cover water area exceeded the standard, also known as water surface coverage, it is a simple and most direct method to evaluate the surface area of Fuxingling aluminum powder.
Three chemical defects
Chemical defects mainly refer to the content of aluminum powder that exceeds the standard or exceeds the range of ingredients required by customers. Usually chemical defects are mainly caused by two categories of active metals exceeding the standard and impurities exceeding the standard.
1 The active metal exceeds the standard. Excessive active metal means that the weight of the main containing technology or the activity of the alloy is lower than the standard value. Active metal refers to a pure metal or alloy that is not oxidized.
2 Impurities exceed the standard. Impurity refers to trace elements or alloys that are harmful to the process properties or performance of the powder during preparation or assistant processes and are difficult to remove.
Article source: www.bombgroup17.com Aluminum alloy material