Primary Process Study On Preparation Of Alumina Ceramic/metal Composite Materials

Ceramic/metal composite materials not only possess the strength of high temperatureand wear resistance, but also the excellence of electrical conductivity as well as thermalconductivity. Consequently, the composite material has aroused extensive attentionworldwide because of its economic prospect and applied value. Due to the inferior wettabilitybetween alumina ceramic and metal, it is unlikely to use the method of pressurelessinfiltration to produce this kind of composite materials. Therefore, the key factor is toimprove the wettability between alumina ceramic and metal. The purpose of this paper is toprepare a layer of titanium coating on the surface of alumina ceramic so that it can possiblysolve the problem of the wettability between alumina ceramic and metal.In the paper，the molten salt-dipped method is used to prepare the titanium coating onthe alumina ceramic with a eutectic salt melt consisting of KCl、NaCl、CaCl₂and elemental Ti.It mainly research the effect for the titanium coating with heating temperature、holding time、the mass proportion of titanium powder and soaking times. Meanwhile，the electroless copperplating method is used to prepare the copper coating on the alumina ceramic using CuSO₄、NaH₂PO₂·H₂O、NiSO₄·6H₂O、Na₃C₆H₅O₇·2H₂O、H₃BO₃as raw material. The paper mainlyresearch the effect for the copper coating with heating temperature、concentration of CuSO₄、concentration of NiSO₄·6H₂O and the pH of copper plating liquid. Analysising the wettinginterface of alumina ceramic together with copper、high chromium cast iron、cast steel byscanning electron microscope and energy spectroscopy.The consequence of this study shows that the maximum value of alumina ceramic perunit has reached in the case of heating temperature above800℃、holding time lasted60minand the mass proportion of titanium powder of11.8. The essential components of coating onthe surface of alumina ceramic are titanium、rutile TiO₂and Ti₃O. Prior to sintering, theessential components of copper-titanium composite coatings consist of titanium and copper,and among of them, the content of copper is more than titanium. The intensity of diffractionpeak in titanium indicates weak slightly, and also there is no titanium oxide with other kindsof crystals. After sintering, the key element of composite coatings comprises titanium andTi₂O₃,and less of Cu₂Ti₄O.During the process of sintering, the intensity of diffraction peak has decreased to a low level between titanium and copper, and also the other sign is that thetitanium has transformed to Ti₂O₃. The titanium coating can greatly improve the wettabilitybetween ceramic and metal and thus a better interface can obtained among of aluminaceramic、high chromium cast iron, cast steel,as well as Cu.