| Liu Zi Canal Site is the former Tongji ditch section of the Sui-Tang Grand Canal, The excavation confirms the former prosperity of this land to us.Tang Dynasty shipwreck, Song docks, and more than twenty porcelain kilns from the country make the site became one of the top ten archaeological excavations in 1999 and national key cultural relics protection units, it is also worthy of being included in the World Heritage List. Especially the porcelain, unearthed in the ruins, the number of rare large variety and kilns, which provides a wealth of information for the study of physical production, transport and export in Tang and Song Dynasty ceramics.as well as the history of development of Chinese ceramics. However, after thousands of years of baptism, due to natural and human factors, coupled with the fragility of ceramics, many ceramics have been unearthed in varying degrees of damage, thousands of porcelain pieces need conservation and restoration urgently. Before the conservation and restoration of two broken porcelain-Petals carved white glaze lamp and green white glazed bowl, we did a scientific testing and analysis, it provides scientific and effective information about the objects, like craftsmanship, origin, artistic and historical value of scientific research, age, etc., and also provide an important basis for the latter to carry out conservation and restoration work. On this basis, with appropriate way to clean porcelain, By comparing selected suitable repair material, and applies it to the test on the body repairing cultural relics, we achieved good results. This provides a theoretical basis for the study about Liu Zi canal unearthed porcelain’s conservation and restorationThe main contents of this paper include the following:K Scientific testing analysis on tiles:Via polarized light microscopy, X-ray fluorescence (XRF), X-ray diffraction (XRD), thermal expansion and other modern analytical instruments, we do the test to analysis the composition, structure, the firing process, surface contamination of Liu Zi canal unearthed porcelain. The preliminary conclusion:lotus petals carved white glazed cup’s body containing a large amount of angular quartz grains and dark iron minerals, in addition to the firing temperature (about 1050℃), he ingredient is dark in color and not dense enough. Carcass main mineral composition is mullite、 some detrital minerals quartz and sillimanite, glaze layer has a needle-like crystals precipitated, the main component of the filler for carved is iron minerals。We found more grinding clinker particles in the greenish white glazed bowl, which may be the kiln’s characteristic of ingredients. Higher firing temperatures (> 1200 ℃) makes compact structure, The main mineral composition of body is mullite and quartz; less impurities and thin glaze layer.2、The analysis of tiles’ origin and age. Combined with the component analysis and the exterior appearance, we compared the origin and age of the two pieces of porcelain; In the body of Petals carved white glaze lamp SiO2/Al2O3 detected in the basin and the white background black flower decoration technology shows its Cizhou system may come from the kilns of the Song and Yuan Dynasties-Anhui Xiao kiln. And the other one, The SiO2/Al2O3 and Green in transparent white glaze has Jingdezhen kiln features. Because of its whole body without ornamentation, it may be an early Northern Song Dynasty porcelain.3、The scientific selection of repair materials. Test showed that the pollutants on the samples witch carved the lotus petals with white glazed lamp on the surface are soil rust. However, the natural pollutants of green white glazed bowl in the cross section are mainly rust. Then the test separately use dilute hydrochloric acid solution (10%) and dilute oxalic acid solution (10%) to clean the surface of these objects, the result is remarkably positive; By using Ailete AB glue, Hezhong AAA, Hxtal NYL-1 to test the flexural strength, the result shows that Hxtal NYL-1 is the strongest of three materials and with the highest transparency and low viscosity, most fit for repairing the high temperature porcelain with light glaze color and well transmittance. The result of putting Hxtal NYL-1 in adhering Enamel bowl is testing. We use gesso, atomic ash and AAA+ ceramic powder, which are commonly used by museum in repairing ceramics, with sample X1 and X2 to go through Shaw D hardness test, the result shows that ceramics AAA+ is the hardness materials of those three and less firm than the tow samples mentioned before, which perfectly fit the solidity required by ceramics repairing. Because of its high plasticity, easy operation, fast drying hardening and easy complementary, it is selected to be the fixing materials of this article. As sample X1 and X2 are high temperature glaze porcelain with smooth and flat surface which is not easy for acrylic paint to grind the surface, we choose pigment powder, which have good performance in avoiding the aging problem and more suitable for high temperature porcelain paint, to color the sample. Based on the precedent data, we choose the black iron oxide when coloring the sample X1. Through Artificial aging test of ultraviolet lamp, we choose acrylic varnish, which better in light performance relatively, in several imitation glaze materials used by the museum to glaze the sample.4、 Innovation of fluorescent recognition effect.Based on an important principle of ancient ceramic restorations-identifiable principles, In this paper, we adding an appropriate amount of phosphor material to make a imitation fluorescent material. Through experiments, the best results are eventually found the proportion of 5% phosphor fluorescent material imitation enamel, making porcelain after the repair to ensure the same heritage itself remains a high degree of integrity of the visual effects in the sun, while the use of ultraviolet light the light source can quickly and easily identify the repair site and not the repair site. This is a good solution to the conflict on modern heritage restoration emphasized "recognizes principle" repair and traditional theory "repairing the old as old." This is the first time the use of the fluorescent effect discrimination repair site in the country, the results of this study provide a reference for the restoration of ancient ceramics. |
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