三石蝋石32%, 同質シャモット40%に, 猿投木節と蛙目粘土をそれぞれ24%および4%ずつ結合剤として加え, 加水, 成形後, これを1400°, 1時間焼成して製作した実験用小型坩堝を用いて, 2種のガラス, すなわちソーダ石灰ガラス (Na₂O・CaO・3SiO₂) とソーダ鉛ガラス (Na₂O・PbO・3SiO₂) の予めカレットとしたものを, 1200°と1400°に熔融し, この温度に達した直後のもの, 2, 3, 4時間後のものを, 炉内から取出して空冷した際に, 各ガラスがそれぞれの坩堝を侵蝕している状態を鏡検してその機構を考察した.
その結果によれば, いずれのガラスでもほぼ同様な侵蝕過程が認められ, 坩堝素地のアルミナ成分の熔解がムライトの熔解にやや先行する結果, 1200°では坩堝素地中の粘土とカオリン質蝋石の各〓焼部分周辺のガラス中に少量のネフェリンを混入したカーネギエイト結晶層が析出しており, 時間の経過と共にこれらの結晶は粘土〓焼部分の周辺から消失し, カオリン質蝋石の〓焼部分周辺に顕著な増加を示す. しかるに, 1400°ではいずれのガラスでも, 最初ダイアスポア仮像周辺のみにカーネギエイトを少量混入したネフェリン結晶の析出が認められ, 時間の経過するにつれて, 結晶は徐々に消失していって, 逆にガラスが坩堝素地内部に浸入し, 外観が白色の極めて薄い侵蝕層を形成するに至る. すなわち, 坩堝素地の表面で若干の成分交換が行われ, それ以後はガラス中への坩堝素地の熔解が, 常に侵蝕層を間にして進んでゆき, 時間が経過するにつれて侵蝕層は少しずつ素地内部に後退してゆく. 全般的に見て, ソーダ石灰ガラスよりもソーダ鉛ガラスの方が侵蝕の度合が強い.

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各種化合物の添加によって良いジルコニアの安定化方法を見出すために研究した. その結果の要点は次のようであった.
(1) ジルコニアの安定化の目的に対してはCaO, MgOの添加が最も好ましく, CeO₂, (Pr, Nd)₂O₃, ThO₂, UO₂, TiO₂, MnO₂等がこれに次いで適当であり, さらにSrO, BaO, NiO, Co₃O₄, Cr₂O₃, CrO₃等がこれに次ぎ, CdO, ZnO, SnO, Ag₂O, Al₂O₃, Na₂O, K₂O等の添加は有効でなかりた.
(2) MgOの添加に比してCaO添加の方が物理的, 化学的, 機械的等の諸性質に対しより良好な影響を与えた.
(3) 耐火物としてはCaOを5%程度以下含むものが最も好ましいようである.
(4) ジルコニアの焼結にはTiO₂, MnO₂, CeO₂, CaO等の添加が有効であり, TiO₂を含むものは3551kg/cm²の圧縮強サを示した.
(5) CaO 5%, ZrO₂ 95%の組成となるようにそのCaOをいろいろな化合形態として添加し, その陰イオンがジルコニアの焼結におよぼす影響についてしらべた. 結晶の成長はCO₃^--を含む場合が最も著しく平均62.7μに達し, PO₄^---を含むものが5.0μで最も小さく, 圧縮強サはF^-を含むものが4967kg/cm², で最も強く, PO₄^---を含むものが2160kg/cm²で最も弱かった.

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Effect of firing operation on physical properties of expanded vermiculite from Fukushima, Japan, was studied from the viewpoints bulk density, brittleness and thermal conductivity. As the firing temperature was raised from 20° up to 1100°C, the bulk density of the vermiculite was diminished from 1.170 down to 0.130. It was desirable the comparatively thin flakes of nearly uniform grain-size were introduced into a heated expansion furnace to receive equal heat treatment. The brittleness of the expanded vermiculite was increased as the firing temperature was raised. But the prolonged duration of firing had no effect on the bulk density and the brittleness in the range of temperature below 1000°C. On the other hand, when fired at 1100°C, the product became blackish and increased the brittleness with prolonged duration of firing over about 1/4min, though there was no appreciable change in less duration of firing. This tendency was strengthen at the temperature above 1100°C. To obtain the maximum expansion of golden material, it was seen from the data presented that Fukushima vermiculites should be subjected suddenly to the temperature from 1000° to 1100°C for a few seconds. Thermal conductivity was decreased with a decrease in bulk density due to an increase in the temperature of firing. The values of thermal conductivity of expanded products, obtained from the unsieved grains of vermiculite, with bulk density of 0.175 were 0.045 and 0.073kcal/m. hr °C at the mean temperatures of 100° and 300°C, respectively. Those values with bulk density of 0.150 were 0.042kcal/m hr °C at 100°C. and 0.075keal/m. hr °C at 300°C. The measurements of thermal conductivity were made with loose-filled samples pressed by 20 per cent.

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In continuing the previous studies (This Journal 62, 785-789 (1954)), the results of further studies were reported by the same authors, as the following abridgement. (1) The strength depression by heating the hardened prismatic test pieces in air at 100 and 60°C for 60, 200 and 300 minutes were systematically tested and the results were fully discussed by comparing with those in the previous paper. (2) Fine powder of broken scrap of electric porcelain insulator, which is called as Scherben and was used already in the previous paper, was also added to the Portland cement sample in the proportion of Cement 1.0 to 1.0, 0.5, 0.4, 0.3, 0.2 or 0.1 of Scherben, and these mixed cement samples were tested on the strength depression by the rapid treatment of heating to cooling from 100, 90, 80, or 50°C to 0, 20, 50, 80 or 90°C. The addition of small amount (about 10-30%) of Scherben to the Portland cement was proved to give good effect to the mixed cement as the cementing material of electric porcelain insulator.

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