Oxalate Coprecipitation Prepared By Diamond Metal Bond

During the past several decades, the application areas of diamond-cutting tool have expanded continuously. The diamond matrix is used to hold diamond particles, and is consumed while diamond particles are being consumed. Among the various matrices used in diamond tools, metal matrix is widly apllied with the advantages of high adhesive strength, wear resistance, long lifespan, etc., therefore it is widely used by many diamond-cutting tool manufacturers. High quality metal matrix can be used as the catalyst in transforming graphite into diamond; it is the future trend for man-made diamond production. Now the common preparation of metal matrix is to mix all metal particles in specific proportion simultaneously. This procedure has a simple workflow, but the metal particle mixing is time-consuming, and the matrix generated lacks homogeneity, consequently resulting in low performance and reduced lifespan of the diamond-cutting tools made with these matrices. These intrinsic drawbacks obviously cause significant waste of time and money; therefore adopting new technique to prepare high quality metal matrix is of tremendous significance.In this study, tri-metal oxalate was used as the precursor of the metal matrix, which is compose of ferrous oxalate, nickel oxalate and cupric oxalate. The precursor were reduced to obtain the metal matrix. This co-precipitation technique is simple, energy efficient, and environmental friendly. The advantages of this technique are precise stoichiometry control and homogeneous metal distribution, as well as the feasible incorporation of rare elements. Moreover the raw material is abundent and inexpensive; therefore the tri-metal oxalate method for metal matrix preparation is very promising and is of high potential.The studies of the paper are outlined below:1. The tri-metal oxalate precursor was prepared by chemical co-precipitation. The goals are improving and equalizing the conversion ratio of the Fe²⁺, Cu²⁺ and Ni²⁺, which could reduce costs and generate the precursor with optimal metal proportion. The filtrate was studied by atomic absorption. The data showed a general result that a high concentration of reaction solution is beneficial. Additionally, longer reaction time, higher temperature and precise control of the solution pH can improve the conversion ratio of Fe²⁺ and Ni²⁺ and help equalize the conversion ratios of metal ions; however, we did observe the decrease of the conversion ratio of Cu²⁺ slightly. We summarized the optimal condition as follows: Fe²⁺ concentration of 0.3 mol/L, reaction temperature at 50℃, reaction time for 2h, pH of 4.0.The co-precipitate was characterized by XRD. The result indicated that the formed co-precipitates are uniformly perfect crystal of oxalates under a variety of conditions and have formed double salt probably.2. Thermal decomposition of the ferrous oxalate was investigated in closed system, N₂ flow and H₂ flow, characterized by high temperature X-ray diffraction analysis, XRD, TG, ICP and TPR. It has been observed that thermal decompositions of ferrous oxalate in closed system and N₂ flow are almost identical. After excluding the...