【作者】 张克华；

【导师】 袁巨龙； 文东辉； 洪滔；

【作者基本信息】 浙江工业大学 ， 机械电子工程， 2009， 博士

【摘要】 蓝宝石（α-alumina,Al₂O₃）是典型的硬脆先进陶瓷材料,作为优良的衬底材料,具有良好的物理和化学性质,普遍用于高速IC芯片、薄膜衬底和各种电子和机械元件。随着电子技术、固体照明技术的发展,对超精密加工技术提出了更高的要求。追求高效和少、无损伤超精密加工,促成了延性域加工技术的出现,也就是说加工脆性材料时,切屑通过剪切的形式被磨粒切除下来,加工后的表面和亚表面没有裂纹产生,也没有脆性剥落时的凹凸不平现象出现,因此延性域加工是一种损伤极小的加工方式,在陶瓷、玻璃、光学元件和半导体领域有广阔的应用前景。为了更好的控制磨粒的延性域加工,本课题组提出了一种“半固着磨具”加工技术,其“半固着磨具”以有机结合剂、磨料为主,在一定的压力和较低温度下成型的新型磨具,该磨具表面磨粒的排列方式具有等高性和均匀性,磨粒之间的结合强度比固结砂轮弱,不会在工件表面造成强制性划伤,磨粒的均匀分布不会产生游离磨粒的加工随机性。具有加工表面损伤层小,加工表面质量的可控性好、批一致性高以及加工效率高等特点。本文基于“半固着磨具加工技术”,对蓝宝石衬底系统地开展了延性域加工的试验研究。利用微纳米力学系统的纳米压入、划痕试验方法,分析了蓝宝石衬底延性到脆性的转变过程和特征,并通过分形理论和试验研究半固着磨具与工件的接触特性,对研磨过程的延性域研磨参数进行了分析;综合纳米压痕、划痕等试验方法和SEM、EDS、AFM、XRD等测试手段,对研磨加工的表面损伤和完整性进行了分析;并对延性域研磨加工进行了评价。论文的主要工作如下:（1）采用纳米压入和纳米划痕等微纳米力学测试手段分析了蓝宝石延性-脆性转化的过程和特征,获得了不发生脆性破坏的临界切削深度约为300nm左右。（2）运用分形理论分析了半固着磨具与工件的微接触行为,对半固着磨具的表面形貌进行了模拟,使用超景深三维显微镜获得半固着磨具表面的粗糙度特征值,由这些特征,生成半固着磨具的三维表面形貌。通过计算和试验获得工件与半固着磨具的接触面积与载荷的关系,为试验参数的设计提供支持。（3）根据临界条件和接触参数情况,根据延性域加工的数学模型,得出了延性域加工的控制参数,并经过游离磨粒与半固着磨具的加工试验对比研究得出:使用粒度为W14的碳化硼磨粒的半固着磨具加工,工件的表面质量优于粒度为W3.5的B₄C磨粒的游离磨粒加工水平。因此半固着磨具加工可以减少游离磨粒加工的工序,提高加工效率。并对半固着磨具加工的工件表面进行了高分辨率的AFM和SEM分析测试,未发现微小裂纹存在,但有类似金属切削的塑性流动产生。采用EDS分析表面塑性流动部分的组成成份为41.1wt%的O,58.9wt%的Al,证明是蓝宝石自身材料,并不是半固着磨具脱落物。因为半固着磨具的磨粒有结合剂粘着,其加工类似于大量的微刃切削,所以能够达到延性加工的目的。（4）延性域加工评价为工件加工后表面和亚表面不存在裂纹,而且其变质层为数百个纳米以下。本文提出了使用X射线小角度掠入技术和纳米压入的方法来测试表面变质层的厚度。几种方法所测得的变质层厚度都在数百纳米左右。更多还原

【Abstract】 Sapphire （α-alumina, Al₂O₃） is one of the best substrate materials, which take on the brilliant physical and chemical property, and it is the typical crisp and hard advanced ceramics material at the same time. Sapphire is extensive used for high speed IC chipset, thin films substrate and electronic component and mechanical element. Along with the development of the technology of electronics and solid state lighting, the higher requirements for ultra-precision processing are suggested, the pursuit for effective and reducing or eliminating the surface defects inducing the ductile regime lapping processing technology, namely, the chip are cut thorough shear style by the abrasive when processing the crisp materials, there are not crack on the processed surface and subsurface and not irregularity caused by crisp peeling. So the ductile regime processing is a next to nothing defects processing style. It is the promising processing style for ceramics, glasses, and optics & semiconductor materials. In order to control effectively the ductile regime lapping, an original technology ’semi-fixed abrasive machining technology’ is proposed by the project group, the ’semi-fixed abrasive plate’ （SFAP） is a new abrasive tool that was molded with the organic bond and abrasive under the lower temperature, whose abrasive is arranged uniform and contour on the surface, the combine intensity of abrasive is weaker than the concretion abrasion wheel, so it could reduce or eliminate the compellent scratch and the processing randomicity of the abrasive distribution could be avoided too. The local acting force on the processed surface is uniform distribution, so the SFAP have the characteristic that the processed surface affected layer is thin, the surface quality controllability is good and have the higher processing efficiency.The ductile regime lapping experimental research is employed based on the SFAP. The critical condition of ductile to brittle transformation of sapphire is studied by the experiment method of nanoindentation and nano-scratch. In order to design the ductile lapping parameter the contact characteristic between the SFAP with workpiece is studied by fractal theory and contact experiment. The testing instrument and method such as nanoindentation, nano-scratch, microcosmic roughness, SEM, EDS, AFM and XRD are used to analyze the surface defect and integrality of the SFAP lapping process. At last the ductile processing appraisal is performed. The main works and research results in the paper are summaried as following:1. The critical condition of ductile to brittle transformation of sapphire was obtained by the nano test method such as the nanoindentation and nano-scratch. The critical cut is about 300nm.2. The contact action between SFAP and workpiece was analyzed by the fractal theory. At first, the surface topography of SFAP was simulated by the fractal theory according to the roughness eigenvalue that was obtained by Digital Microscope Resources Center （DMRC） （VHX-600 Series, the Keyence Corporation）. The roughness eigenvalue of simulation surface was matching with the measured value, so the simulation results could be used to carry out the contact analysis. The relations of contact area with load were obtained by calculating and experiment; it was the basis of the experiment parameter.3. The mathematic model of ductile regime processing was set up according to the critical condition and contact parameter, and then the ductile control parameter was obtained. The contrast experiment of SFAP and loose abrasive processing were made to get the following results: the surface topography of workpiece that was processed by the W14 B4C SFAP was superior to that were processed by the W3.5 B4C loose abrasive. So the better surface topography could be obtained processing used the SFAP than the loose abrasive under the same time and condition. The SFAP processing could reduce the working procedure and increase production efficiency. The high resolution AFM and SEM were used to test the workpiece surfaces that were processed by SFAP, the microcracks were not found and the plastic flow similar metal-cutting were found. The plastic flow matters were measured by the EDS, the results showed that the compositions of it were 41.15% 0 and 58.85% Al, so the chips were the sapphire and not the cast of the SFAP. The abrasive of the SFAP were bonded by the bonding agent, so the abrasive processing was similar the micro-blade cutting and could achieve the ductile regime processing. On the basis of the above, the SFAP processing was more efficient and precision than the same granularity loose abrasive.4. The estimate of the ductile regime processing was that there were not flaw on the processed surface and the affected layer was less than hundreds nanometer. The nanoindentation and low-angle X-ray diffraction technology were employed to test the thickness of the affected layer based on the analysis of the existing test method. The measured value of the several test method were about 400nm. It could explain that the SFAP processing in this dissertation were in the ductile regime.更多还原