Recherche Of Synthesis And Technology Of SiC, SiC_w/SiC Composites

SiC material has excellent properties such as electrical, mechanicaland other excellent performance.It was widely used in metallurgy,chemical industry, energy, biotechnology, semiconductor mater ials andother fields. However, the traditional process of synthesis SiC in hightemperature.And then, high energy consumption and many terribleenvironmental pollution and other issues was brought.Material scholarsseeked new green process with their hard work for synthesis SiC.Inrecent years, material scholars have found some new synthesisprocesses, from low temperature to high temperature, the highperformance SiC ceramic and its composites and SiC nanomaterials wassynthesis by different processes. Successful exp loration and preparationof SiC material has various forms as SiC single crystal material, SiCheterogeneity and homogeneity ep itaxy process es was also succeeded.SiC denpend on these studies which brought SiC to wide application.This paper prepared SiC, SiC(w)/SiC material, studied the key issures ofprocesses and the influence on different process on SiC and SiC(w)/SiC.The new via of synthes-is process by bring in Al-catalytic waseffectively worked at at low temperature for synthesis SiC andSiC(w)/SiC. The main studies of this paper as follows.1. The phenolic resin and filter paper was heated as the C source.H201#methyl-s ilicone oil as the silicon source used to synthesis SiCwhen it pyrolys is at suitab le temperature.The sample has low SiCcontents and its yield and defect can’t get high purity of SiCmaterials,we can found a large amount of amorphous phase in theproduct. Although succeed of the prepared block material, the bulkmaterial density ispoor, poor physical properties.2. SiC(w)/SiC composites were prepared by in-s itu reaction of carbon and silicon through conventional synthes is sintering. Carbonsource and silicon source were introduced by filter paper coated withsilicon powder phenolic resin mixture suspension. The growthmechanism was also investigated as well. The result shows that theprepared nanowires possess s mooth surface, uniform-sized and aspectratio up to103at1430℃. The growth mechanism of the nanowires issupported by VS growth model. A new way of prepared SiC（w）/SiCcomposite by one step was proposed.3. Si powder used as the silicon source,and phenolic resinpyrolysis C used as carbon source,can be able to synthesis of SiCmaterials under low temperature，to a certain content under the catalysisof Al.By comparison， we can found that during the Al catalyt icpreparation of SiC samp le, the formation of S iC reduced about400℃temperature, but， by the reaction of the trend and the high temperatureare still helpful for the preparation of SiC, however, the introduction ofAl for SiC nanowires, nanorods formation has certain inhibition, when alarge of Al are introduced it can effectively refine the SiC grain size.Bycontrast in different temperature in the experiment it can be found thataluminum catalytic preparation of SiC nanorods optimal generationtemperature at1250℃.4.In the process of preparation of SiC materials using SiO2assilicon source.The introduction of appropriate amount of Al on thereaction of catalytic effect obviously,Under a part of raw materialratio in experimental design。It can be the successful preparation of S iC,however, the process in the preparation of the final product of thepresence of large amounts of difficult to remove impurities, such asAl2O3, elemental Si, etc.This makes the process be difficult to get SiCmaterials in high purity theoretically。 The catalytic mechanism isstudied，The introduction of Al, making Al thermal reduction reactionjo int into the original C thermal reduction reaction, more vio lentthermit reduction reaction makes the system’s temperature reduced, andthe reduction of the elemental Si, makes the reaction more eas ily.5. Fe2O3as the catalyst synthesis ed SiC at the defferent temperature. SiO2and C powder as the Si and C source can notsynthesis SiC. Ti catalyst displaced Al obtained to TiC and Ti3SiC2without any SiC. These results show that Al catalyst was valid.