Studies on Sintering and Melting Process of Powders by Laser Irradiation and Induced Heating Method

本研究项目的目标是建立一套适用于材料合成工艺、功能生坯生产工艺和烧结工艺的工艺设计和控制方法。一系列的研究成果如下：1.结合粉末技术，综述了精细陶瓷作为功能材料的研究进展。指出了评估和标准化的意义，并介绍了杂交技术和行业的动向。从仪器工程的角度对激光辐照法制备超细粒子进行了研究。结果表明，基于布朗凝聚模型的模拟结果能够较好地解释颗粒长大机理。利用非稳态换热模型分析了材料内部的换热情况。为了对陶瓷粉末进行表征，对不同厂家生产的几十种材料粉末进行了sa…测试。更多的Me陶瓷生产工艺。一系列数据给出了绿色密度与其形成条件之间的经验关联。这种关联性使得可以根据出料密度和压实压力来预测坯料密度。找出了生坯与烧结密度之间的定量关系，阐明了工艺条件对生坯密度和烧结密度的影响。结果表明，烧结体密度与生坯密度之间可以通过简单的表达式进行关联，所提出的图解分析方法有助于了解工艺条件对烧结体密度和生坯密度的影响。作为梯度功能材料研究的基础，提出了三种能够平滑、连续地改变成形材料成分的技术。在每种技术中，都对工作条件进行了实验研究，以控制成分分布。这些技术的吸引人的特点是它们的简单性，从而便于它们在其他材料合成过程中的应用。较少

The objectives of this research project are to establish a series of process design and control methodology which can be suitabiy applied to the material synthesis process, production process of functionally green body and sintering process. A series of researches yields results as follows.1. Development of fine ceramics as a functional material is reviewed in connection with powder technology. Significance of evaluation and standardization pointed out, and movement of hybridization in technologies and industries is introduced.2. Production of ultrafine particles by laser irradiation method has been studied from a view point of apparatus engineering. It is shown that simulation results based on Brownian coagulation model can explain particle growth mechanism. Heat transfer inside the substance is also analyzed by making use of unsteady heat transfer model.3. To characterize ceramics powders a few tens of material powders produced by different manufacturers have been subjected to the sa … More me ceramics production process. A series of data yields an empirical correlation between green density and their forming conditions. The correlation enables green densities to be predicted from tap density and compaction pressure.4. The quantitative correlation between green and sintered density has been found out to clarify the effects of process condition on them. It is shown that the sintered density can be correlated with the green density by simple expression, and that graphical analysis proposed can be help to under stand the effect of process conditions on sintered and green density.5. As a basis research of functionally gradient material, three kinds of technique are proposed which can smoothly and continuously vary the composition of formed material. In each technique the working conditions have been experimentally investigated to control the composition profile. The attractive feature of these technique is their simplicity, which thus facilitates their application to other material synthesis processes. Less