Adapted Heat Treatment for Phase Transformation of NiS Inclusion in the Heat Strengthened and Tempered Glass

Dr. Chihiro Sakai and Masashi Kikuta

To avoid spontaneous breakage of heat-strengthened and tempered glass is one of most important subjects of glass products in buildings and automobiles. Several attempts have been so far made for empirical basis of heat treatment or phase transformation of NiS by many authors. However, we found few investigations into the nucleation frequency of the phase transformation of NiS inclusions, although there are many studies of the rate of transformation with respect to the holding temperature and time.

Effective frequencies of nucleation and crystal growth of NiS inclusion depend on the rate of the temperature increase in the heat soak process of tempered and heat-strengthened glass. They also depend on the composition of crystalline NiS (the compositional ratio of Ni and S and additional elements such as Se and Fe in NiS). Maintaining the temperature and time of NiS at the maximum temperature affects the growth rates of transformation from the alpha to beta phases of crystalline NiS. New technical methods, i.e. the heat treatments necessary to transform from the alpha to beta phases of NiS, are described in this paper.

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The Authors

Dr. Chihiro Sakai Nippon Sheet Glass Techno-Research Co., Ltd. Nippon Sheet Glass Techno-Research Co.,Ltd. My major is phase petrology, mineralogy and rock-forming mineralogy. I have get a dgree of doctor for phase petrology in Kyoto University, 1960. Now, I belong in the R&D and testing tection ( NSG Tec... Read more