Investigation On Preparation Technology Of Cold Isostatic Pressing Forming And Properties Of Getter Material

Getter material is widely used in electric vacuum devices of the key materials, internal heating type getter with heating element for convenient use, good performance in vacuum devices, especially in vacuum MEMS devices has great application prospect. In order to meet the uniformity and high precision of engineering preparation of getter with heating element, a porous Ti-based getter material was prepared by isostatic pressing forming technology using NH4HCO3 as pore forming agent in this thesis. The surface morphology, porosity, specific surface area and sorption properties of the materials were analyzed by SEM, Archimedes drainage method, BET and sorption performance testing device. The sorption properties of porous Ti-based getter and internal heating type getter fabricated by isostatic pressing forming technology were studied, and the change law of gas sorption curve were analyzed. Concrete research results are listed as follows:Firstly, porous Ti-based getter was fabricated by mould pressing forming technology. The influence of the addition amount and particle size of NH4HCO3 on the sorption performance was studied. The results revealed that the sorption properties of samples decreased with the increase of NH4HCO3 particle size. The sorption properties of samples increased first and then decreased with the increase of NH4HCO3. When activated at 350 ?, 400 ? or 450 ?, the porous Ti getter with addition of 20 wt% NH4HCO3 has the best hydrogen sorption properties. When activated at 700 ? or 600 ?, the porous Ti getter with addition of 25 wt% NH4HCO3 has the best hydrogen sorption properties. Moreover, the addition of NH4HCO3 significantly reduced the activation temperature of the porous Ti-based getter.Secondly, the sorption properties of porous Ti getter and Ti-Mo getter were analyzed and compared. The results showed that the sorption properties of porous Tigetter with addition of 10wt% NH4HCO3 were higher than that of porous Ti-Mo getter with the same NH4HCO3 content, and it was also higher than that of Ti-Mo getter without NH4HCO3. Therefore, adding a certain proportion of NH4HCO3 in porous Ti getter can improve the sorption performance and porosity. Porous Ti getter can be used in some occasions instead of Ti-Mo getter.Finally, porous Ti getter with internal heating was fabricated using isostatic pressing forming technology. The effect of hydrostatic pressure and activation temperature on the sorption properties were studied, the difference between isostatic pressing forming and other preparation process was also studied. The results showed that the porosity and relative density has the very big difference with different pressure. Samples preparatived by 150 MPa pressure showed good sorption properties and mechanical strength. When activation temperature exceeded 400 ?, the sorption speed of porous Ti getter with internal heating had obvious improvement. The sorption properties rose with the increase of activation temperature. The appropriate activation temperature was 700 ?. The sorption performance of getter fabricated by isostatic pressing forming was better than that of mould pressing forming and injection molding, and the getter has the characteristics of high consistency and good mechanical properties.