Effect of Preparation Technology Parameters on the Restriction Performances of Unitary Titanium Porous Restrictor

摘要

Unitary titanium porous restrictor was prepared by a sintering welding technique. The results indicated that the restriction performance of unitary Ti porous restrictor was not only dependent on the morphology and particle size of the original powder, but also influenced by the molding pressure, sintering temperature and sintering pressure. The restrictor obtained from titanium powder with large particle size or spherical morphology possesses big porosity, large pore size and high permeability but low restriction. Instead, the restrictor derived from fine powder with irregular morphology had small porosity, narrow pore size but high restriction performance. In addition, the restriction ability of the titanium porous restrictor metals increased by increasing of molding and sintering pressure and the sintering temperature. However, a much higher sintering temperature induced a bad welding status, which ascribed to excessive sintering shrinkage of the porous restrictor, and the cracks between the porous body and the compact shell easily occurred. Finally, the strength of the dense Ti shell would decrease due to the flaws caused by the grain growth during sintering process. It was an ideal method to avoid the grain growth at high temperature through increasing the molding and sintering pressure and decreasing the sintering temperature, which could obtain a good sinter behavior and air tightness between the porous body and the Ti shell, thus, which satisfied the requirements in the applications.