The Research Of The Process Of The Preparation Of ZrC-WC Powder And Its Composite Materials

Transition metal carbides are a kind of high mechanical strength and hardness material with metallic luster,conductive,and the characteristics of high melting point.They are suitable for the cutting tool and tool materials,but its application is limited by its poor sintering performance and low fracture toughness.ZrW₂O₈ powder is synthesised by coprecipitation in this paper,and the preparation technology is explored,and ZrC-WC composite is prepared using the ZrO₂-ZrW₂O₈ composite powder synthesised with carbon under common wet ball mill mixed by reaction sintering,after phase composition and microstructure of the material are analysised by X-ray diffractometer?XRD?,scanning electron microscope?SEM?,laser particle size analyzer analytical methods,and the phase composition and organization morphology change and optimize the process is studied in detail.Results show that when precursors prepared in this case that Zr⁴⁺solution dissolving PEG200 is mixed in W⁶⁺solution dissolving PEG2000 and adjusted the value of p H of the solution to 2,then calcined in 600?/2h and 1160?/2h can prepare ZrW₂O₈ powder with small particles size,narrow particle size distribution and high purity.The purity of ZrW₂O₈ powder is calculated by XRF which is prepared after the optimization process,which is 97.95%.The average particles size d₅₀0 of ZrW₂O₈ powder is about 0.88?m and particles size distribution coarse end particle size d₉₀0 is about 1.73?m.ZrO₂-ZrW₂O₈ composite powder with different W content is prepared using optimization process of ZrW₂O₈ powder,ZrO₂-ZrW₂O₈ composite powder has ZrW₂O₈ and ZrO₂ phase,the average particle size is about 1?m,coarse end particle size is about 2?m,is consistent with scanning pictures.ZrO₂-ZrW₂O₈ composite powder is mixed with C,and the ZrC-WC composite material is synthesized by the carbon thermal reduction process,and the?Zr,W?C solid solution is successfully synthesized with the temperature increase.With the increase of WC content,the solubility of W in the ZrC increases and forms?Zr,W?C solid solution,when WC content increases untill45%,witch reaches the maximum solid solubility.When the solubility of WC content is more than 45%,the solubility of W in the ZrC reduces,W is existed in the form of elemental W and WC,which can not into ZrC.ZrC-WC composite materials with different contents of W are prepared by reaction sintering,its surface has a lot of holes.?Zr,W?C solid solution phase are formed in different contents of W materials,ZW30 material is homogenous solid solution phase.The ZW40 materials and ZW45 materials contain a small amount of rich W phase in addition to the solid solution phase.ZW50 materials contain the solid solution phase and some WC phases of precipitation,and the ZW67 materials contain solid solution phase and undissolved WC phase.ZW45 materials attain the maximum solid solubility,which is 44.57%.Precursor powder of ZrO₂-ZrW₂O₈with 45mol%W and ZrO₂-ZrW₂O₈ powder calcinated in 600?/2 h and after1200?/2 h have almost no loss of W content.After ZrO₂-ZrW₂O₈ powder is sintered in 2200?/1 h forming ZrC-WC material,and the loss amount of W is about 3 mol%.