GOALI: Measurement of Liquid Phase Sintering Stresses to Model Warpage During Densification

这项研究计划涉及罗格斯大学和他们的工业合作伙伴圣戈班工业陶瓷（诺顿先进陶瓷有限公司）之间的合作努力。研究氮化硅在滚子轴承和阀门等零件制造中的尺寸控制。 由于使用精加工金刚石砂轮进行磨削会增加成本，因此即使烧结过程中产生的少量翘曲也可能妨碍零件的经济制造。 翘曲的主要原因可归因于烧结炉中的温度梯度。 有限元（FE）技术将模拟烧结过程，以确定在温度梯度烧结过程中的变形应变张量。 在这样的研究中获得的基本知识将提供更好的控制炉加热速率，保持温度，加压速率，夹具和零件在制造过程中的位置。 将测量FE技术的所有输入参数，但大部分研究将集中在测量FE分析所需的烧结应力上。氮化硅中的烧结应力和蠕变速率将在1500 C和1950 C之间进行的实验研究中测量。 通过对氮化硅的这些研究，将增强关于液相烧结系统中的烧结应力以及a到B相变对烧结应力的影响的知识。 作为一种模型材料，氧化铝/钙长石玻璃的烧结应力也将被测量，以更好地了解在液相烧结系统中影响烧结应力的参数。该项目的成功完成可能会为其他工业高性能陶瓷部件节省大量成本。

This research program involves a collaborative effort between Rutgers University and their industrial partner Saint Gobain Industrial Ceramics (Norton Advanced Ceramics Co.) to study dimensional control of silicon nitride in manufacturing parts such as roller bearings and valves. Even a small amount of warpage from the sintering process may prevent the part from being economically manufactured due to the added cost of grinding with the finishing diamond wheels. A major cause of warpage can be attributed to temperature gradients in the sintering furnace. Finite element (FE) techniques will model the sintering process to determine the strain tensor of distortion during sintering in a temperature gradient. The fundamental knowledge gained in such a study would provide better control of furnace heating rates, hold temperatures, pressurizing rates, fixturing and placement of parts during manufacturing. All the input parameters for the FE technique will be measured but much of the research will focus on measuring the sintering stresses necessary for the FE analysis. Sintering stresses and creep rates in silicon nitride will be measured in experimental studies conducted between 1500C and 1950C. Knowledge regarding the sintering stresses in liquid phase sintering systems and the effect of the a to b phase transformation on sintering stress will be enhanced by these studies of silicon nitride. As a model material the sintering stress of alumina/anorthite glass will also be measured to better understand parameters affecting sintering stresses in liquid phase sintered systems. The successful completion of this project may lead to significant cost savings for other industrial high-performance ceramic components.