STUDIES ON SPECIAL FINE CERAMIC BODIES (METAL CERAMICS) OBTAINED FROM OXIDE AND METAL POWDERS. I

Abstract

The authors, in connection with his previous studies on special steatite obtained from talc and metal powders (Japanese Patent No. 124041, 1938), began the study on special fine ceramic bodies (to be called metal ceramic) from oxide and metal powders, and reported here the preliminary study. The main points are briefly abstracted from the original Japanese communication, as following:(1) Oxide materials were selected following six samples: (a) alumina, (b) zinc oxide, (c) magnesia, (c) chromic oxide, (e) silica and (j) lead oxide, and used in the state of fine powder.(2) Two kinds of metal powder (a) aluminium powder and (b) zinc powder were selected, but (c) magnesium powder was delayed to be used in the next paper.(3) The proportion of oxide powder to metal powder was 98-85 parts to 2-15 parts, the intimate mixture in the state of dry powder was moulded under 300-1000kg/cm2 pressure to the cylindrical (Dia.; 20mm and Length: 30mm) or plath (Breadth: 30mm, Length: 60mm and Thickness: 15mm) piece, and then burned at 1450-1500°C for 1-3 hours.(4) Sample, above obtained were tested on various physical properties and discussed the merits and demerits of their results. Some samples of ZnO and Zn powder in n% (signed as ZnO-Zn-n) and Al2O3 and Al powder in n% (Al2O3-Al-n) gave good results, but other samples used MgO (as MgO-Zn-n, MgO-Al-n, etc.) gave bad results in repeated teat of quick heating and cooling in water or steam under pressue (10kg/cm2 and about at 178°C), owing to the hydration of free MgO or low burning temperature.(5) The defects were observed as following: (a) Some mineralizer, flux or oxidizing agent is to be used, (b) The burning temperature is to be higher than 1500°C, (c) The burning time is to be longer than 3 hours, (d) The mixing ratios of metal powder is to be larger than 10-15% in the present study, etc. These points are to be further studied, which are now being fully carried on and will be reported in the next papers.