Between a power module, CPU, or LED package and its heat sink, two apparently flat metal surfaces still contain microscopic roughness and air gaps. These discontinuities consume part of the available temperature difference at the interface and can prevent the heat sink from being used effectively.
Reading low thermal resistance through the interface
Lixing Thermal Grease is described as a grey, silicone-based, high-viscosity thermal interface material. Its engineering role is not to replace the heat sink; it fills small gaps between the component and heat-spreading surface to create a more continuous conduction path. The official page lists grades from 2 to 10 W/m·K and thermal impedance below 0.126 °C·in²/W. The selected grade and assembled result still require confirmation under the actual application conditions.
Three mechanisms that matter directly
First, the viscous paste can occupy spaces between surface asperities, reducing the effect of low-conductivity air gaps. Second, the applied layer must be continuous yet controlled: too little may leave voids, while excess thickness lengthens the conduction path through the material. Third, contact pressure, flatness, and application uniformity jointly change void content and effective contact area, so a single material property cannot predict total system performance.
Engineering formula: thickness and area thermal resistance
R = ΔT/q = L/λ. This is an engineering model for a flat slab with one-dimensional, steady-state, approximately uniform heat flux. R is area thermal resistance (m²·K/W), ΔT is the temperature difference between surfaces (K), q is heat flux (W/m²), L is thickness (m), and λ is thermal conductivity (W/(m·K)). Source: NIST SP 260-173. The model excludes interface voids, pressure, roughness, lateral losses, uneven application, and other series resistances; it is not a measured or guaranteed value for this product.
Core technical points
- The verified appearance is a grey, high-viscosity paste intended for interface gap management.
- The official page lists thermal conductivity grades from 2 to 10 W/m·K; confirm the specific grade.
- The published thermal impedance is below 0.126 °C·in²/W and should not be treated as total assembled-system resistance.
- The published non-flowing description supports interface placement, while long-term thermal cycling still needs application validation.
- Published applications include CPU, GPU, power-module, and LED thermal interfaces.
Selection and assembly checks
Start by defining dissipated power, available interface area, and the surface condition of both the component and heat sink. Then control the application method, clamping condition, and bond-line consistency. Witness samples, controlled dispensing, temperature-drop monitoring, and thermal-cycle inspection can provide application-specific evidence. For grade and condition comparisons, consult the official product page and confirm the details with the technical team.
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