Fundamental Studies On The Formation Of High Glossiness Granite Surface

In the process of stone machining, grinding and polishing which are the main ways to increase the decorative value of stone, are applied in the final stages to obtain high glossiness surface. Recently, there are still many technical problems in the stone grinding and polishing has not been solved. The technology of getting high glossiness surface which the glossiness exceeds 100 is mastered by few countries such as Japan and Italy. Compared to these countries, the granite machined by the domestic factories whose glossiness can only reach about 80,which is just as good as the half-product of foreign decorate stone. The benefits of the domestic stone industry will be increased several times if the key technologies of the high glossiness stone grinding can be developed.Many researches on granite grinding and polishing have been done in several university and research institutes. But most of former research works follow the conventional way and the research methods are almost the same. In this paper, a new idea is pointed out. The physical and chemical characteristics, microstructure and the formation mechanisms of the many kinds of stone glossiness surfaces are studied. Some useful information can be obtained after the studies. This paper wants to find sally ports, by this converse method, to improve the level of the technology research in the domestic stone industry. The fundamental investigations of this paper are carried out:1. Comprehensive analysis including the physical and chemical characteristics and microstructure of high glossiness granite surfaces are analyzed by employed the SEM, electron probes, XRD and glow mass spectrogram. On the basis of the firsthand data, it is show clearly that there aren't the gloss film, with amorphous or microcrystal forms after grinding and polishing processes on the granite glossiness surface.2. The temperatures on the machining contact zone were studied theoretically and experimentally when diamond disks grind granite with the vertical spindle surface grinding. The theoretical results well correspond with the experimental results. Both the theoretical results and experimental results are shown that the average surface temperature on the contact zone are below 100-150C in the normal grinding. The studies negated the view which the temperature at the machining contact zone is above 1000C assumed by past research. So it also proved that the temperature in the grinding zone is not enough to form a new phase on the granite surface.3. In order to discover the formation mechanisms of the high glossiness granite surface; a comprehensive experiment is designed to observe the formation process of theglossiness surface. Temperature, surface morphologies, surface structure, surface roughness and surface glossiness at each separated stage ranging from sawing to polishing are monitored. The achievements of experiments show clearly that there are obvious traces of ductile flowing on the granite machined surfaces, although the granite is hardness and brittleness material. The formation mechanisms change from the brittleness removal to the ductile removal, with the decreasing of diamond grit size in the grinding and polishing processes. The material removal method is ductile removal and the ductile flowing spreads to a larger scale from the point to line to the whole surface, and the high glossiness surface is formed at last. There are damaged layer of few microns under the glossiness surface, which the crystal lattices are distorted for the ductile flow. It means that the high glossiness surface of the granite is a low roughness surface, which is formed under the condition of the ductile removal. The formation mechanisms revealed in this paper, are very important to improve the stone grinding and polishing technologies in the domestic stone industry.4. The experiment for examining the stone surface glossiness and surface roughness further shows that the stone surface glossiness is monotone increasing as the decrease of the surface roughness. When the surface roughness...