Hiroaki Okano

TL;DR: In this article, a circuit board is provided in which an aluminum layer (12a) and a copper layer (13) are laminated on the side of a ceramics plate.

TL;DR: In this article, a reaction-bonding and post-sintering process was applied to fabricate pressureless sintered β-Si 6− Z Al Z O Z N 8− Z (Z ǫ = 1-3) ceramics with monoclinic ZrO 2 added to the starting powder.

Abstract: Reaction bonded silicon nitride ceramics have been produced from Si powders of different particle size and both with and without zirconia as a nitride catalyzing element. The effect of the ZrO 2 on the nitridation rate of the specimens was studied as a function of temperature, and the mechanism of enhanced nitridation was discussed. At all temperatures, the degree of nitridation of specimens sintered with ZrO 2 was higher than those without additions for all particle sizes. In the case of nitridation of specimens produced without ZrO 2 , the degree of nitridation was dependent on particle size, with larger sizes resulting in less nitridation. For specimens with ZrO 2 the finest powder also showed highest transformation, but there was no difference in the degree of nitridation of medium and coarse powders. It was found that during heating of the specimens the ZrO 2 was transformed to ZrN at low temperature and enhanced nitridation is considered to be due to this phase re-converting to ZrO 2 at higher temperature and thereby supplying nitrogen to the interior of the specimens. At lower temperatures, the strength of the specimens with ZrO 2 were higher than those without, attributed to the enhanced nitridation. However, comparing strengths of fully nitrided specimens, those with ZrO 2 were lower than those without, thought to be due to the presence of ZrO 2 particles disrupting the connectivity of adjacent silicon nitride grains.

TL;DR: The tensile strength at breaking point was over 12 MPa almost comparable to that of PTFE itself as discussed by the authors, and the degree of modification was gradual from the upper layer to the inner layer.