Due to its wide range of applications as a superhard material,polycrystalline diamond(PCD)has been used in oil-and gas-drilling,tool cutting,making of wear-resistant parts.At present,the average size of industrial synthetic PCD is above the micron dimension,but synthesizing the PCD with a size below the micron dimension remains a tough challenge.In this work,we succeeded synthesizing sub-micron polycrystalline diamond under high temperature and high pressure using the infiltrating technique.The samples were...