청동주조 토제범(土製范)의 재질과 제작기법 연구－ 경주 동천동 출토 토제범을 중심으로 －

Abstract

This study examined the actual reconstruction drawing, composite mineral, particle size and property test,fine organic matters, color differences and main ingredients of the earthen mold excavated in Dongcheondong,Gyungju. The cross-section of the inner mold and outer mold divides into inside (1st layer) andoutside (2nd layer), with organic matters mixed outside. The cross-section has been altered due to heat and form removal agent. X-ray analysis revealed thatthe layer was made of minerals with high transmissivity and only quartz particles were observed througha polarizing microscope. The inside of cross-section in SEM observation identified enlarged air gap, withcrack developed in the center, but no changes observed on the outside. The particle size of the compositesis almost the same for the inner mold and outer mold and is silt clay loam. The ratio between silt clay andsilt clay loam was about 2.7:1 and 2.9:1 respectively. In the property test, the density and absorption rate ofinner mold and outer mold were similar, but porosity was different, with inner mold of 27.36% and outermold of 31.09%. The color difference of cross-section seems to have been caused by the spread of soot onthe 1st layer surface for removal of form or by the covering of ink to protect the 1st layer. Composite mineralanalysis revealed the same composition for the inner mold and outer mold, except for the magnetite thatwas detected in the inner mold alone. As for the main ingredient analysis, the average content of SiO2 was71.64% and that of Al2O3 was 14.59%. As for the sub-ingredients, Fe2O3 was 4.51%, K2O 3.06%, Na2O, MgO,CaO, TiO2, P2O5 and MnO was less than 2%.