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

该研究项目涉及罗格斯大学及其工业合作伙伴圣戈班工业陶瓷公司(Norton Advanced Ceramics Co.)的合作努力。研究氮化硅在滚子轴承、阀门等零件制造中的尺寸控制。即使是烧结过程中产生的少量翘曲，也可能会阻碍零件的经济制造，因为使用精加工的钻石砂轮会增加磨削成本。翘曲的主要原因可归因于烧结炉内的温度梯度。有限元(FE)技术将模拟烧结过程，以确定在温度梯度中烧结过程中变形的应变张量。从这项研究中获得的基本知识将提供更好的炉子加热速度、保温率、加压速度、夹具和制造过程中零件的放置的控制。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。氮化硅的烧结应力和蠕变速率将在1500C到1950C之间进行实验研究。氮化硅的这些研究将加深人们对液相烧结系统中烧结应力的认识，以及a到b相变对烧结应力的影响。作为模型材料，还将测量氧化铝/钙长石玻璃的烧结应力，以更好地了解影响液相烧结系统烧结应力的参数。该项目的成功完成可能会为其他工业高性能陶瓷元件带来显著的成本节约。

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.