With the advent of the 5G era, thermal silicone pads are increasingly favored by the electronics manufacturing industry. The main reason is that thermal silicone pads are widely used, such as filling cooling devices, communication hardware, new energy vehicle control units, and drones. , base station, LED lighting, LCD display, medical beauty equipment, etc.; in these applications, the thermal silicone pad will produce a certain compression to bridge the gap to achieve good thermal conductivity.
When choosing a thermal silicone pads, you cannot just look at thermal conductivity, blocking voltage, thickness, density, and hardness is also very important; when choosing a thermal silicone pad, you must first consider the product structure, such as shape, specification, breakdown, temperature resistance range, thickness, density, thermal conductivity We all know that the thermal conductivity of a thermal silicone pad is an important indicator to measure its performance, and its hardness also affects the performance of the thermal silicone pad; many people have doubts about the hardness of the thermal silicone pad when choosing, so CoolThermo came to Analyze the hardness of the thermal silicone pads.
First of all, what is the concept of hardness?
Hardness, a technical term in physics, the ability of a material to locally resist the pressing of a hard object into its surface is called hardness. The local resistance of a solid to the intrusion of foreign objects is an indicator for comparing the softness and hardness of various materials. Hardness is used to characterize the degree of softness and hardness of a material, which refers to the ability of a material to resist local deformation, especially plastic deformation, indentation or scratching.
So, what is the hardness of the thermal silicone pad?
One advantage of high-quality silicone thermal pad is that the material is usually soft, and the softness precisely refers to the hardness of the silicone thermal pad. Its hardness directly reflects the soft and hard compressibility of the silicone thermal pad. A very important parameter in the physical properties of silicone thermal pads.
Thermal Silicone Sheet Hardness Test Standard
Since different test methods are specified, there are different hardness standards. The mechanical meanings of various hardness standards are different and cannot be directly converted to each other, but can be compared through tests. Common hardness is classified according to the test method: scratch hardness, indentation hardness, callback hardness. According to the specific hardness names, there are: Rockwell hardness, Brinell hardness, Leeb hardness, Shore hardness, etc.
According to the standard ASTM D2240 “Standard Test Method for Testing Rubber Hardness with Durometer”, the thermal silicone sheet uses Shore hardness to express its hardness. The corresponding measuring instrument for Shore hardness is the Shore hardness tester, which is mainly divided into three categories: A type, C type and 00 type. The measurement principle is exactly the same, the difference is the size of the stylus, especially the diameter of the tip, the 00 type is the largest, and the A type is the smallest. The Shore A durometer is suitable for measuring hard thermal pads; the Shore 00 durometer is suitable for measuring soft thermal pads.
Shore hardness belongs to indentation hardness. The test method is to insert a Shore hardness tester into the material to be tested. The pointer on the dial is connected to a needle through a spring, and the needle is used to pierce the surface of the tested object. The value displayed on the dial is the hardness. value.
Is the hardness of the thermal silicone pads good or low?
The lower the hardness of the thermal silicone pads, the softer the product and the higher the compression rate, which is suitable for use in low-stress environments. Conversely, the higher the hardness of the thermal pad, the harder the product and the lower the compression rate. Under the same application conditions, products with low hardness have higher compressibility, shorter heat conduction paths, shorter heat transfer time, and better heat conduction effect than products with high hardness.
However, it is not that the lower the hardness, the better. The thermal conductive gasket has a certain hardness so that it is not easy to deform. Generally speaking, thermally conductive gaskets with higher hardness have better mechanical properties. In the application, it is necessary to comprehensively consider the actual situation to select a thermally conductive gasket with appropriate hardness.