【正文】 nd to be a suitable method for organic binder removal. Finally, the burnedout preforms are sintered in a PbOrich atmosphere to 9798% of the theoretical density. No problems have been encountered with controlling the weight loss during sintering of these posite preforms, even for those finescale, highsurface area preforms which are intended for high frequency ultrasound.Figure 4 illustrates the surfaces of asmolded and assintered fibers, showing the presence of shallow fold lines approximately 10pm wide, which are characteristic of the injection molding process. The fibers exhibit minor grooving along their length due to ejection from the tool. Figure 5 shows the capability of near netshape molding for fabricating very fine scale preforms。當(dāng)壓電陶瓷5H的原料物質(zhì)被考慮到受注射成型設(shè)備污染鐵的敏感性，這些有關(guān)的測(cè)量方法對(duì)于這種注射成型的壓電陶瓷材料可以忽略這類污染。每一行的要素都包括三個(gè)錐角(0，1和2度)以及兩個(gè)直徑()。最近，這種方法已被研究用作生產(chǎn)熱發(fā)動(dòng)機(jī)渦輪部件的技術(shù)。(2)在極化過(guò)程中發(fā)生率高的介電擊穿是起于在一個(gè)典型的大型陣列遇到一個(gè)或多個(gè)有缺陷的纖維的顯著概率。畢業(yè)設(shè)計(jì)(論文)外文資料翻譯系　　部： 機(jī)械工程系 專 業(yè)： 機(jī)械工程及自動(dòng)化 姓 名： 學(xué) 號(hào)： 外文出處： A. Safari and D. J. Waller, Fine Scale PZT Fiber/Polymer Composites” 附 件： ；。在過(guò)去的五年里，為了提高制造行業(yè)的生存能力并降低材料成本已經(jīng)多次嘗試簡(jiǎn)化傳感器的組裝工藝。如圖1所示，注塑成型方法已被用于壓電陶瓷的成型。為了容許成型收縮，預(yù)加工的工件尺寸維持在50mmX50mm，以盡量減少在制模周期中的冷卻部分折斷外層纖維的可能性。*粉末的提供方是俄亥俄州貝德福德的摩根士丹利公司，105A街區(qū)。 PZT element dimensions only 30pm wide have been demonstrated. The assintered surface of these elements indicates that the PZT ceramic microstructure is dense and uniform,n consisting of equiaxed grains 23pm in diameter. Figure 3: Injection Molded 13 Composite Preforms. Figure 4: Scanning Electron Micrographs of Asmolded(Upper) and Assintered (Lower) Surfaces of PZT Fibers Figure 5: Finescale 22 Composite formed by Near Netshape olding (Upper Micrograph). Assintered Surface(Lower Micrograph).In order to demonstrate the layup approach for posite fabrication, posites of approximately 10 volume percent PZT5H fibers and Spurrs epoxy resin were fabricated by epoxy encapsulating laidup pairs of injection molded and sintered fiber rows followed by grinding away the PZT ceramic stock used to mold the posite preform. Figure 6 shows posite samples made from freshlypounded PZT/binder mixture and from reused material. Recycling of the pounded and molded material appears to be entirely feasible and results in greatly enhanced material utilization. Table 1 pares the piezoelectric and dielectric properties of injection molded PZT ceramic specimens with those reported for pressed PZT5H samples prepared by the powder manufacturer. When the sintering conditions are optimized for the PZT5H formulation, the piezoelectric and dielectric properties are parable for both materials. Since the donordoped PZT5H formulation is expected to be particularlysensitive to iron contamination from the injection molding equipment, the implication of these measurements is that such contamination is negligible in this injection molded PZT material.SummaryCeramic injection molding has been shown to be a viable process for fabricating both PZT ceramics and piezoelectric ceramic/polymer transducers. The electrical properties of injection molded PZT ceramics are parable with those prepared by conventional powder pressing, with no evidence of deleterious effects from metallic contamination arising from contact with the pounding and molding equipment. By using ceramic injection molding to fabricate posite preforms, and then la