High-pressure generation by a multiple anvil system with sintered diamond anvils and study of pressure measurement

(1)用烧结金刚石的多个砧座系统产生高压。第二级MA8高压系统的砧座采用烧结金刚石，MA6系统第一级的砧座采用碳化钨砧座。烧结金刚石块(Syndax L555，De Beers Diamond Co.Ltd.)是用碳化硅粘结的，因此，该复合材料对X射线具有良好的透明性。烧结的钻石被抛光成立方体，它们的角被截断以形成MA8设备的砧头。截边长度分别为0.5 mm和1.0 mm。对于TEL=1.0 mm的顶锤，氧化镁压力介质的八面体边长为3.4 mm。产生的压力是通过测量金的晶格常数来确定的。当TEL=1.0 mm时，产生的压力高达28 Gpa，当TEL=0.5 mm时，产生的压力高达41 Gpa。(2)大体积高压产生为了在更大的体积中获得更高的压力，我们必须清除三个因素，即1)大的作用力…更高的利用率，2)材料的高强度，3)强度的大压力导数。无结合剂烧结金刚石可以明确这三个因素，但不可能得到它。烧结的钻石块(Syndie，1285/D27，De Beers Diamond Co.Ltd.)被抛光成立方体，它们的角被截断以形成MA8设备的砧头。抛光后的烧结钻石立方体的边长为8.45 mm。目前使用的砧座的截边长度(TEL)为2 mm。在这种情况下，很容易产生高达28 Gpa的压力(Fe85%V%15α-epsilon转变)，但压头的压力增加到6 Gpa，因此不可能增加压力。(3)式高压装置本实验所用的高压系统由八个模块组成。一块由1块烧结金刚石锤(8.45 mm)和7块WC立方体锤(8 Mm)组成。金属垫片放在阀瓣之间。系统由DIA-30按下。以Fe_(80)%V_(20)%的最小电阻点为基准，获得了超过35 Gpa的压力。较少

(1) High-pressure generation by a multiple anvil system with sintered diamond. Sintered diamonds are employed for the anvil of second-stage MA8 high pressure system and the anvil of fist stage is used tungsten carbide anvil for MA6 system. The sintered diamond blocks (SYNDAX L555, De Beers Diamond Co. Ltd) are cemented with silicon carbide, therefore, the composites have excellent transparency for the x-ray beam. The sintered diamonds are polished to form cubes and their corner are truncated to form the anvil head of the MA8 apparatus. The truncated edge lengths are 0.5 and l.0mm. The edge length of the octahedron of the magnesia pressure medium is 3.4mm for the anvil with TEL=l.0mm. The pressure generated was determined by measuring the lattice constant of gold. Pressures generated up to 28GPa for TEL=l.0mm and 41GPa for TEL=0.5mm.(2) High pressure generation In large volume In order to attain higher pressure in larger volume, we have to clear three factors, that is, 1) the large forc … More e utilized, 2) high strength of material, and also 3) the large pressure derivative of strength. The no bander sintered diamond can be clear the three factors, but it is not possible to get it. The sintered diamond blocks (SYNDIE, 1285/D27, De Beers Diamond Co. Ltd) are polished to form cubes, and their corners are truncated to form the anvil head of the MA8 apparatus. A side of a sintered diamond cube after polishing has 8.45mm in length. The truncated edge length(TEL)of the anvil used for the present is 2mm. In this case, it is easy to generate pressure up to 28GPa(Fe85%V%15 alpha - epsilon transition), but press of the anvil head increase up to 6GPa, therefore, it is not possible to increase pressure.(3) 64-type high pressure apparatus The high pressure system used present experimentare constituted with eight blocks. A block is consisted with one sintered diamond anvile (8.45mm) and 7 pieces of WC cubic(8mm) anvils. Metal gaskets are put in between the an vils. The system is pressed by DIA-30. Pressures in excess of 35GPa were obtained on the basis of minimum point of electrical resistance of the Fe80%V20%. Less