Microstructure and thermal stability of the Cu-ZrB2 and CuCr1Zr-ZrB2 composites prepared by gas pressure infiltration

Abstract

Composite materials based on Cu matrix have a wide range of applications because of their extraordinary features such as high thermal conductivity and high mechanical strength. The preparation of Cu-ZrB2 and CuCr1Zr-ZrB2 composites via gas pressure infiltration technology is described in this work. In contrast to most ceramic materials, ZrB2 is electrically and thermally conductive. All tested samples, i.e. prepared from the ZrB2 porous preform with a porosity of 40 % were infiltrated with molten Cu or CuCr1Zr alloy. Microstructure and homogeneity after infiltration were examined by SEM-EDS microscopy. The interface between the Cu matrix and ZrB2 ceramics was explored by TEM microscopy. As-infiltrated composites were thermally cycled up to 800 • C with heating and cooling rates of 3 • C min −1 in an argon atmosphere.

Microstructure and thermal stability of ZrB2 powder infiltrated by molten Cu and CuCr1Zr alloy

“…7b). All measurements of thermal expansions confirmed the results with infiltrated ZrB 2 preforms [1].…”

“…The ZrB 2 powder infiltrated by pure copper was inserted into the graphite container. The details of the Cu/ZrB 2 infiltration technique have been published in the previous paper [1]. However, the ZrB 2 powder infiltrated by molten copper alloy was fixed in the molybdenum container.…”

“…6. As a ZrB 2 reference, the thermal behaviour of ZrB 2 preform measured in the previous paper was taken into account [1]. The thermal expansion in the first cycle is slightly different when compared to 2-5.…”

“…In a previous paper [1], Cu/ZrB 2 and CuCr1Zr/ ZrB 2 composites were prepared using gas pressure infiltration method. ZrB 2 preforms were successfully infiltrated by molten metal.…”

“…thermal protection components in hypersonic aerospace re-entry vehicles (wing's leading edges and nose caps), propul-*Corresponding author: tel. : +421 2 32401038; e-mail address: nada.beronska@savba.sk sion systems components, thermocouple sheaths, refractory crucibles, furnace heating elements, hightemperature electrodes for plasma applications and metal evaporator boats [1][2][3][4][5]. For thermal plasma processes, the most undesired feature is the high wear rate of used elemental electrodes.…”