Kiyoshi Hirao

Title: Kiyoshi Hirao: Innovator in Silicon Nitride Technologies

Introduction

Kiyoshi Hirao is a prominent inventor based in Aichi, Japan, known for his significant contributions to the field of silicon nitride technologies. With a total of six patents to his name, Hirao has developed innovative methods that enhance the production and properties of silicon nitride substrates and ceramics.

Latest Patents

Hirao's latest patents include a method for producing silicon nitride substrates. This method involves several steps, including the preparation of a raw material powder containing silicon powder, a rare earth element compound, and a magnesium compound. The process requires careful control of the composition, with the rare earth element compound at 1 mol % to 7 mol % and the magnesium compound at 8 mol % to 15 mol %. The method also includes forming the raw material into a sheet article, nitriding it in a nitrogen atmosphere at temperatures between 1200°C and 1500°C, and sintering the sheet article afterward.

Another notable patent is a method for producing porous silicon nitride ceramics with high strength and low thermal conductivity. This method involves adding more than 10 volume % of rodlike beta-silicon nitride single crystals into a mixture of silicon nitride raw powder and a sintering additive. The formed body is then sintered to develop elongated silicon nitride grains, resulting in a sintered body with enhanced properties.

Career Highlights

Throughout his career, Kiyoshi Hirao has worked with esteemed organizations such as the Fine Ceramics Research Association and the Japan Agency for Industrial Science and Technology. His work has significantly advanced the understanding and application of silicon nitride materials in various industries.

Collaborations

Hirao has collaborated with notable colleagues, including Motohiro Toriyama and Syuzo Kanzaki, contributing to the development of innovative technologies in the field of ceramics.

Conclusion

Kiyoshi Hirao's contributions to silicon nitride technologies through his patents and collaborations have made a lasting impact on the industry. His innovative methods continue to pave the way for advancements in material science and engineering.