Method for preparing pore diameter controllable porous capillary core

Abstract

The invention relates to a method for preparing a pore diameter controllable porous capillary core. The method comprises the following steps of: uniformly mixing soluble salt powder which does not react with matrix powder in the matrix powder of capillary core sintering raw materials, and coldly molding the mixed powder into the capillary core with the needed shape; and performing pressureless sintering or pressure sintering on the molded raw materials under the protection of inert gases, and washing off the soluble salt to prepare the capillary core. The method has the advantages of simple preparation process, no need of a pore-forming agent and low cost, and the capillary core with high strength, controllable porosity and controllable pore size distribution is prepared.

Description

technical field [0001] The invention relates to a preparation method of a porous material, in particular to a preparation method of a porous capillary core with controllable pore size. Background technique [0002] Porous materials have a well-developed pore structure and have been widely used in aerospace, transportation, environmental protection, petrochemical and other fields. As an important application, the capillary core in the loop heat pipe LHP (Loop heat pipe) evaporator utilizes the capillary suction and permeability of porous materials, and the performance of the capillary core is the key to the overall performance of the loop heat pipe. . Capillary cores that can meet the requirements of loop heat pipes not only require a certain porosity, but also have certain requirements for their strength. In the traditional sintered capillary core, the porosity of the capillary core is generally changed by changing the sintering pressure or adding sintered volatile organic...

AI Technical Summary

Problems solved by technology

At present, the vast majority of research is to add volatile or flammable pore-forming agents, such as starch, polymethyl methacrylate (PMMA), ammonium bicarbonate (NH 4 HCO 3 ), microcrystalline cellulose (MCC), etc., but the addition of such pore-forming agents often leads to the release of a large amount of gas or volatile substances during the sintering process. When the pore-forming agent is added in a large amount, it is easy to cause cracks or even collapse of the sample. Defects, in addition, the decomposed gas is oxidizing, and for metal powders that rely on atomic diffusion bonding, it is easy to cause a decrease in the bonding force, so that it is impossible to obtain a capillary core that meets the strength requirements

This type of pore-forming agent has a small limit addition amount, and the maximum porosity that can be obtained under the premise of meeting the strength requirements is correspondingly low, generally around 50%.

In addition, the pore size generated by this method is generally large and the pore size distribution is not uniform.

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