Fabrication of sintered wick in micro -grooved pipe
The sintering heat pipe is an ideal component in solving the heat dissipation of high heat flux chips. The heat pipe with sintered wick structure in micro-grooved pipe was featured with low heat resistance, high bond strength and hard to dryout. According to the sintering theory, the manufacturing process of sintered wick could be divided into four phases: reduction phase, sintering starting phase, sintering preservation phase and sintering cooling phase. The sintering temperature, sintering time and sintering atmosphere about fabrication of the innovative sintered wick were also inspected. The result was discoveried that 100 mesh spherical copper powders had high porosity and low radial shrinkage at the sintering temperature of 950°C for 3 hours and the mandrel could be easily pulled out. It was also found that the oxidation reduction process could manufacture new micro structure—the segmentation cracks structure on the surface of copper powders.
Temperature Response of Heat Transport in a Micro Heat Pipe
A detailed mathematical model for predicting the heat transport capability and temperature gradients that contribute to the overall axial temperature drop as a function of heat transfer in a micro heat pipe has been developed. The model utilizes a third-order ordinary differential equation, which governs the fluid flow and heat transfer in the evaporating thin film region; an analytical solution for the two-dimension heat conduction equation, which governs the macro evaporating film region in the triangular corners; the effects of the vapor flow on the liquid flow in the micro heat pipe; the flow and condensation of the thin film caused by the surface tension in the condenser; and the capillary flow along the axial direction of the micro heat pipe. With this model, the temperature distribution along the axial direction of the heat pipe and the effect on the heat transfer can be predicted. In order to verify the model presented here, an experimental investigation was also conducted and a comparison with experimental data made
Fabrication of v-groove gratings in InP by inductively coupled plasma etching with SiCl4/Ar
Inductively coupled plasma (ICP) etching of v-grooves in InP is demonstrated. We use SiCl4/Ar at a temperature of 25 °C and a broadband photoresist mask. Optimized v-groove etch parameters are discussed, in addition to the effect of various etch parameters on the etch rate and profile. This process utilizes a small amount of mask erosion, and careful control of the chemical and bombardment enhanced etch processes to give a self-limiting v-groove etch profile, which is insensitive to crystallographic directions of the InP.