1. Material composition
The material of the square magnet directly affects its magnetic strength, durability and applicable environment. Different materials have their own advantages and limitations. Common magnet materials include:
Neodymium (NdFeB): Neodymium magnets are one of the strongest rare earth magnets currently available and are widely used in projects with high strength requirements, such as motors, sensors, speakers, etc. However, a major disadvantage of neodymium magnets is their sensitivity to temperature and corrosion, so they usually require coating protection when used in harsh environments.
Samarium Cobalt (SmCo): Although SmCo magnets do not have the magnetic strength of NdFeB, they perform well in high temperatures and extreme environments. This material can still maintain its magnetism at temperatures up to 300°C, making it very suitable for engineering projects under high temperature conditions. In addition, SmCo has excellent corrosion resistance and is suitable for marine or humid environments.
Ferrite: Ferrite magnets are low-cost and corrosion-resistant, but have weak magnetic forces and are suitable for applications with low strength requirements, such as speakers, toys, and small motors. Ferrites also have good high temperature resistance, but due to their weak magnetic properties, they are usually used in places where magnetic force is not required.
Alnico: A major advantage of Alnico magnets is their excellent high temperature resistance. They can operate at temperatures above 600°C, so they are often used in sensors or electrical components in high temperature environments. However, this type of magnet is more expensive and has weak magnetic force, so it is not usually used in places where magnetic force is extremely high.
Choosing the right material according to the specific needs of the project can ensure that the performance of the magnet matches the project needs and avoid failure or cost increase due to improper materials.

2. Magnetic Strength
The magnetic strength of a magnet is one of its most important properties, usually measured in pull force or magnetic flux density. When selecting a magnet, the magnetic strength must match the project needs. For example:
NdFeB magnets are suitable for situations that require strong adsorption or retention due to their high magnetic flux density, such as motors, medical equipment, etc. Strong magnetic fields can act on objects across a certain distance, so they are very suitable for projects that require remote magnetic effects.
The assessment of magnetic requirements should be based on the object that needs the magnet in the project. For example, a lighter object can be fixed with a weak magnet, while a heavy object or an occasion where the suction force needs to be maintained for a long time requires a strong magnet. In addition, the external interference that the magnetic field needs to overcome is also important, such as other magnetic fields that may exist nearby, electromagnetic interference, etc.
The balance between magnetic strength and cost also needs to be paid attention to. Over-selecting high-strength magnets will increase costs, while magnetic forces that are lower than required will affect the normal operation of the project. Therefore, the optimal balance between performance requirements and costs should be considered when selecting.

3. Size and shape
The size and shape of square magnets will significantly affect their performance. Generally, the larger the size of the magnet, the stronger the magnetic force it produces. The characteristic of square magnets is that their magnetic field is evenly distributed, which is suitable for certain specific engineering projects, but the following points should be considered when choosing the size:
Thickness and magnetic force: The thickness of the magnet determines the depth of the magnetic force. Thicker magnets can produce stronger magnetic fields and can act on objects farther away. For applications that require long-distance magnetic effects, thicker square magnets may be the best choice. Thinner magnets are suitable for use in places with limited space, such as internal components of electronic devices. Although their magnetic force is limited, multiple magnets can be combined to achieve the desired effect.
Shape and installation: The shape of square magnets also affects their applicability in specific applications. Compared with round magnets, square magnets have advantages in fixing and aligning because they can contact other square or flat objects more stably, which is very helpful for engineering projects that require precise positioning and fixing.
Space and weight restrictions: In some engineering projects, the volume and weight of magnets are also limiting factors. For example, in aerospace or portable devices, weight is critical, so it is necessary to choose small square magnets that are light and have strong magnetic properties.

4. Operating temperature
Temperature is an important factor affecting the performance of magnets. All magnets have a Curie Point, which is the temperature at which the magnet loses its magnetism. Square magnet of different materials behave differently at high temperatures, so when selecting square magnets, the temperature conditions in the project must be considered:
NdFeB magnets will significantly reduce their magnetic force at high temperatures exceeding 80°C, so caution is required when using them in high temperature environments. If the project involves high temperature operation, it may be more appropriate to choose samarium cobalt magnets or alnico magnets because they can better maintain magnetism at high temperatures.
Temperature fluctuations: If the temperature changes frequently in the project, the temperature resistance of the magnet is more critical. Some magnets may temporarily lose magnetism during temperature fluctuations, but they can recover after cooling, while others will permanently lose part of their magnetism. Therefore, understanding the stability of the magnet material in temperature changes is crucial to ensure the long-term stable operation of the project.

5. Corrosion resistance
In some applications, magnets may be exposed to humid or corrosive environments, such as marine equipment or outdoor projects. At this time, it becomes particularly important to choose magnets with good corrosion resistance or surface treatment of the magnets:
Although neodymium iron boron magnets have strong magnetism, they are easy to oxidize and rust in humid environments. Therefore, it is usually necessary to perform plating treatment on their surface, such as nickel plating, zinc plating or epoxy resin coating, to enhance their corrosion resistance. It is very important to choose the appropriate plating according to the specific use environment.
Samarium cobalt magnets and ferrite magnets have good corrosion resistance themselves, especially suitable for humid, marine or chemical environments. These magnets do not require additional coatings and are able to maintain stable performance over time in harsh environments.

6. Magnetic Stability
During long-term use, the magnetic field of a magnet may change due to changes in external conditions or the environment in which it is used. For example, exposure to a strong external magnetic field may cause some magnets to become less magnetic or even fail. Therefore, choosing magnet materials with good magnetic stability is critical to the success of your project:
Demagnetization resistance is an important indicator, especially when subjected to external magnetic fields, physical shock, or temperature changes. Some magnets tend to lose some or all of their magnetism under these conditions, while others have strong demagnetization resistance and can maintain stable magnetism for a longer period of time. For example, samarium cobalt magnets excel in demagnetization resistance and are well suited for long-term, harsh environment use.
Impact of physical shock: In some projects, magnets may be subjected to vibration or mechanical shock, and it is particularly important to choose magnets with strong shock resistance. Physical shock may cause damage to the internal structure of the magnet, which in turn affects the magnetic output, so magnets used in these environments must have high shock resistance.

7. Cost and availability
When selecting magnets, cost is often an important consideration. Magnets of different materials, sizes, and treatments have different costs. Choosing the right magnet requires finding a balance between performance requirements and budget constraints:
High-performance magnets such as NdFeB magnets are more expensive, but due to their strong magnetic properties, it is possible to reduce the number of magnets used, thereby reducing the cost of the overall project. This is very useful for high-end, magnetically demanding projects. Although individual magnets are expensive, their high performance may bring long-term cost benefits.
Low-cost options such as ferrite magnets are weaker in magnetism, but they are inexpensive and suitable for projects that do not require high magnetic force and need to be used in large quantities.