부산대학교 도서관

A high strength electrical porcelain was developed using inexpensive raw materials and standard porcelain manufacturing methods. This was accomplished by reinforcing the glassy phase with strong needle-shaped crystals of mullite, which were grown during the firing cycle. An additional increase in strength was gained by decreasing the closed porosity of the fired material to nearly zero. The breaking strengths of unglazed samples were 25,000 to 30,000 psi, compared to 10,000 psi for standard electrical porcelain. The electrical properties of this material are approximately equivalent to those of standard porcelain. The cost of this material is approximately two cents per pound (5 percent) higher than standard porcelain due to increased raw materials costs and a small additional labor cost. Advantages of high strength porcelain are smaller and lighter insulators, less chance of breakage, increased safety and therefore a savings in total cost to the utility user.