华南理工大学学报（自然科学版）
華南理工大學學報（自然科學版）
화남리공대학학보（자연과학판）
Journal of South China University of Technology (Natural Science Edition)
2015年
9期
113-120
,共8页
李敏%袁巨龙%吕冰海%姚蔚峰%戴伟涛
李敏%袁巨龍%呂冰海%姚蔚峰%戴偉濤
리민%원거룡%려빙해%요위봉%대위도
剪切增稠抛光%氮化硅%流变行为%应力状态%材料去除%精密抛光
剪切增稠拋光%氮化硅%流變行為%應力狀態%材料去除%精密拋光
전절증주포광%담화규%류변행위%응력상태%재료거제%정밀포광
shear-thickening polishing%silicon nitride%rheological behavior%stress condition%material removal%precision polishing
基于剪切增稠抛光（STP）的加工原理分析 Si3 N4陶瓷超精密加工的控制策略，考察所制备的含有立方氮化硼（CBN）磨粒的剪切增稠抛光液的流变行为，分析工件抛光前后表面形貌变化及表层应力状态，研究其抛光特性．结果表明：抛光液具有可逆的剪切增稠与稀化效应，可达到 STP 加工工艺用抛光液的要求；改变磨粒粒径，可以控制 Si3 N4加工效率与表面质量，且材料去除量和表面粗糙度的理论值能够反映试验值的变化；STP 加工Si3 N4为持续微切削的“柔性抛光”，初期为脆性剪切、粘着磨损去除，后期为塑性去除；当磨粒粒径达到纳米级时，表层应力状态由初始残余拉应力变为压应力，说明 STP 不仅能高效去除原有表面损伤层而且新引入的损伤小；随着抛光时间的延长，去除量先快速增大而后趋缓；抛光90 min 后，去除率由初期的5．00～2．40μm ／h 降至3．24～2．04μm ／h，表面粗糙度 Ra由108．9～111．1 nm 降至22．0～10．7 nm；抛光150min 后，Ra可降至9．6～7．2 nm，实现了 Si3 N4陶瓷粗抛后的精密抛光．
基于剪切增稠拋光（STP）的加工原理分析 Si3 N4陶瓷超精密加工的控製策略，攷察所製備的含有立方氮化硼（CBN）磨粒的剪切增稠拋光液的流變行為，分析工件拋光前後錶麵形貌變化及錶層應力狀態，研究其拋光特性．結果錶明：拋光液具有可逆的剪切增稠與稀化效應，可達到 STP 加工工藝用拋光液的要求；改變磨粒粒徑，可以控製 Si3 N4加工效率與錶麵質量，且材料去除量和錶麵粗糙度的理論值能夠反映試驗值的變化；STP 加工Si3 N4為持續微切削的“柔性拋光”，初期為脆性剪切、粘著磨損去除，後期為塑性去除；噹磨粒粒徑達到納米級時，錶層應力狀態由初始殘餘拉應力變為壓應力，說明 STP 不僅能高效去除原有錶麵損傷層而且新引入的損傷小；隨著拋光時間的延長，去除量先快速增大而後趨緩；拋光90 min 後，去除率由初期的5．00～2．40μm ／h 降至3．24～2．04μm ／h，錶麵粗糙度 Ra由108．9～111．1 nm 降至22．0～10．7 nm；拋光150min 後，Ra可降至9．6～7．2 nm，實現瞭 Si3 N4陶瓷粗拋後的精密拋光．
기우전절증주포광（STP）적가공원리분석 Si3 N4도자초정밀가공적공제책략，고찰소제비적함유립방담화붕（CBN）마립적전절증주포광액적류변행위，분석공건포광전후표면형모변화급표층응력상태，연구기포광특성．결과표명：포광액구유가역적전절증주여희화효응，가체도 STP 가공공예용포광액적요구；개변마립립경，가이공제 Si3 N4가공효솔여표면질량，차재료거제량화표면조조도적이론치능구반영시험치적변화；STP 가공Si3 N4위지속미절삭적“유성포광”，초기위취성전절、점착마손거제，후기위소성거제；당마립립경체도납미급시，표층응력상태유초시잔여랍응력변위압응력，설명 STP 불부능고효거제원유표면손상층이차신인입적손상소；수착포광시간적연장，거제량선쾌속증대이후추완；포광90 min 후，거제솔유초기적5．00～2．40μm ／h 강지3．24～2．04μm ／h，표면조조도 Ra유108．9～111．1 nm 강지22．0～10．7 nm；포광150min 후，Ra가강지9．6～7．2 nm，실현료 Si3 N4도자조포후적정밀포광．
In the investigation,the control strategy of ultra-precision machining of Si3 N4 ceramics is analyzed on the basis of the principle of shear thickening polishing (STP),and the rheological behaviors of the prepared STP slurry with cubic boron nitride (CBN)abrasives are discussed.Then,the variations of the surface morphology and sur-face residual stress state of Si3 N4 ceramics before and after the polishing are analyzed to reveal the polishing charac-teristics of STP.The results show that (1)the slurry displays a reversible shear thinning and shear thickening be-havior,which meets the requirement of the slurry for processing STP;(2)the machining efficiency and surface quality of Si3 N4 ceramics can be controlled by changing the grain size of CBN abrasives,and the theoretical values of the material removal and the surface roughness can reflect the change of experimental values;(3)the STP re-moval of Si3 N4 is a continuous micro cutting process named "flexible polishing",in which the brittle shear or the adhesive wear is employed in the initial stage of machining and the ductile removal of the microscopic plastic flow is used in the later stage;(4)when the grain size reaches nanoscale,the surface stress state of Si3 N4 will change from the initial residual tensile stress to the compressive stress,which means that the STP can efficiently remove the damage layer of the original surface and produce merely new small damage;(5)with the extension of the polishing time,the material removal amount of Si3 N4 first increases quickly and then tend to increase slowly;(6)after poli-shing for 90 min,the material removal rate decreases from 5.00 ~2.40 μm /h to 3.24 ~2.04 μm /h and the sur-face roughness Ra reduces from 108.9 ~111.1 nm to 22.0 ~10.7 nm;and (7)after polishing for 150min,Ra can be reduced to 9.6 ~7.2 nm,which indicates that STP process achieves the precision polishing of Si3 N4 ceramics.
