Powder-Metallurgical Free-Form Microchanneling Process for Producing Metallic Microreactors

We verify effectiveness of the concept of powdermetallurgical free-form microchanneling with functional microchannel lining. It is based on a microscopic infiltration phenomenon during liquid phase sintering of a powder mixture of metals with different melting points. A shaped compound of an organic binder and a powder metal with lower melting point is used as the sacrificial core that gives the shape of the microchannel. The resultant microchannel is surrounded by an alloy layer, which is expected to have useful propertie

Powder-Metallurgical Process for Producing Metallic Microchannel Devices

We investigated a simple and economical method for producing free-form microchannels in metal bodies. The concept for our process is based on a microscopic infiltration phenomenon that often occurs during liquid phase sintering of a mixture of metal powders with different melting points. A shaped compound of the metal powder with lower melting point and an organic binder are used as the sacrificial core that gives the shape of the microchannel. A body-metal powder compact that includes the sacrificial core is sintered at a temperature between the melting points of the sacrificial-core metal and body metal. The organic binder is removed during heating of the powder compact, and infiltration of molten sacrificial-core metal into the body-metal powder produces a microchannel and a lining layer. We examined following combinations of metal powders: titanium-aluminum, nickel-aluminum, copper-tin, and iron-copper. Metallographic observations confirmed that microchannels were produced in the metallic bodies in all these systems. Furthermore, in the case of the titanium body metal with an Al-Cu alloy sacrificial-core metal, the inner wall of the microchannel was smoother than the case of titaniumwith aluminum. The copper content of the sacrificial-core metal influenced the composition and structure of the microchannel lining. [doi:10.2320/matertrans.47.2137