Research On Fabrication And Properties Of Bulk Isotropic Carbon Prepared From Superfine Powder Of Vapor Growth Carbon Balls

The application of carbon/graphite materials in our daily lives can be said to be ubiquitous,especially in the context of the rapid development of industrial technologies and the acceleration of aerospace exploration projects.We need excellent mechanical strength and high isotropy.Bulk carbon materials.The vapor-grown carbon sphere ultrafine powder was prepared by pretreatment of low density,low-density bulk isotropic pyrolytic carbon prepared by chemical vapor deposition method.The physico-chemical properties,thermal stability and thermal expansion properties of the four binders were compared.The laboratory-made mesophase pitch binder and the superfine powder of vapor-grown carbon balls were selected to prepare sinter able powder.This paper discusses the influence of mechanical properties of block carbon materials,the sintering principle of the hot pressing process,the influence of different molding methods on the properties and structure of block carbon materials,and the optimization of the preparation process of block carbon materials.Friction and abrasion properties of the bulk isotropic carbon materials and commercial carbon material ISO88 were studied.The main findings of the study are as follows:（1）Low density block isotropic pyrolysis carbon by changing the chemical vapor deposition process.The gas growth carbon ball ultrafine powder was obtained by crushing ball mill and acidifying treatment.The particle size distribution and graphitization of gas growing carbon balls are affected by different ball milling machines and acidifying time.Carbon spheres with particle sizes 1-2μm and I_D/I_G 0.21were prepared by dry ball milling and 24-hour acidification.（2）By comparing the physical and chemical properties,thermal stability and thermal expansion of the four binders,adenosine phosphate with the highest carbon yield and good thermal stability was selected as the binder of block isotropic carbon.（3）The density of raw billets of gaseous growth carbon pellets was increased and then decreased with the increase of temperature pressure time.The density of thick billet increases with compression pressure and then decreases,but the arc crack defects appear after carbonization.Block carbon has a volume density of 1.72 g/cm^-3 and a bending strength of 76.3 MPa at 110 MPa.（4）Veldt hardness 138 HV,isotropic 1.03 was obtained by optimizing the gas growth of carbon pellet ultrafine powder mixed with AP-MP binders with bulk density of 1.7 g/cm^-3,compressive strength 274 MPa,bending strength 86.3 MPa,Young modulus 15.6 GPa.The friction coefficient of isotropic IPC is lower than that of commercial carbon material ISO88 and the wear quantity is higher than that of commercial carbon material ISO88.