| Currently, the titanium alloy is focused on as a kind of good aerospace materials because of its low density, good elevated-temperature strength, excellent metal creeping properties and high melt temperature. But at the same time, it is adversely affected by furnace gas at heating operations. The surface of the titanium alloy is very liable to suffer in oxidation reaction, and results in formation of the oxidative film and penetrative layer that is hard and brittle, which may cause a great loss of the titanium alloy as high as 2.2% by weight of the metal. Comparing to proceeding heat treatment in a vacuum furnace or under non-oxidizing condition with argon atmosphere, the coating technique possesses more advantages, such as more simple preparative technological process, better protective effect, lower cost, and more suitable for applying in large workpiece. During heat treatment process, protecting titanium alloy against oxidation is an effective ways of improving the quality and utilization ration of titanium alloy products. The high-temperature-resisting glass-ceramic protective coating was successfully prepared by solid phase synthesis on the basis of protective mechanism and design rules, which can effectively protect the titanium alloy from oxidizing. The studies are as followed:1. On the basis of comprehensively analyzing literatures, three kinds of protective mechanism was provided, and six pieces of design rule was constituted according to the true fact of heating operations, which could be an introduction for preparing coating.2. According to protective mechanism and design rules, the major components of the coating were selected by means of comparing the standard free energy of formation of Ti02 and those of the other oxides. The standard free energy was obtained through thermodynamics computation on the basis of the relationship of free energy and temperature.3. The suitable coating materials were selected successfully of repeated test by solid phase reaction method. The components of coating, aids, high temperature melting process, cold ration, ball milling process, and mechanical strength of coating were investigated in great detail. The protective coating applied in the titanium alloy heatmtreatment was successfully prepared and the optimum synthesis technique process was explored and determined.4. The resistant oxidation protective effect of coating was characterized by means of energy dispersive spectroscopy(EDS) analysis and oxygen weight-gain testing in different scope temperature. The results showed that the prepared coating could protect effectively titanium alloy against oxidizing between 500癈 and 1200癈.5. It is a kind of temporary coating, and the coating could be removed easily from the surface of titanium alloy substrate after heat treatment process. The crystallization ability of coating was investigated by X-ray diffractometry(XRD), and the results showed that the coating was liable to peel off because of the creating crystallization phase. But if the coating created a lot of crystallization phase after heat treatment, the coating would peel off as soon as titanium alloy specimens were taken out of high temperature furnace, which made titanium alloy be oxidized again because the temperature on the surface of titanium alloy was still very high. The crystallization ability of the coating is controlled by the coating component and it can be adjusted in order to avoid completely crystallizing.6. The thermodynamics wet process of the coating and the affecting wetting factors were discussed. At the same time, the wetting ability of the coating was investigated by means of measuring wetting angle of the coating on the surface of titanium alloy. In order to improve the wetting ability of the coating, some surface active oxides were added into the coating during preparation process. The prepared coating in this paper could wet well the surface of the titanium alloy and protect it against oxidation.7. The model of oxygen diffusion transport through...
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