EFFECT OF THE METHOD OF PRODUCTION OF POROUS POWDER-METALLURGY MATERIALS ON THEIR CAPILLARY PROPERTIES (REVIEW)

The unique features of liquid infiltration in capillary-porous powder metallurgy materials (CPPM) are discussed. The effect of the productio n method on the maximum height and rate of capillary rise of a liquid in CPPM is clarified. It is shown that in materials with a uniform por e structure, and the same average pore size, the maximum value of H-ma x is attained when the form factor of the initial powder particles is a minimum. The highest values of liquid infiltration rare at closely s imilar heights of capillary rise (within 5-7%) were obtained in CPPm w ith a variable pore distribution prepared from mixtures of powders wit h different particle sizes (pseudo-fluidization method), or in CPPM wi th a biporous structure prepared by the sintering of a previously oxid ized powder, by compacting metal powder with a pore-forming agent, as well as by the cathodic deposition of a porous copper structure from e lectrolytic solution.