Effect of tungsten based coating characteristics on microstructure and thermal conductivity of diamond/Cu composites prepared by pressueless infiltration

Abstract

Tungsten coatings were deposited on diamond particles by vacuum magnetron sputtering. The coated diamond particles were firstly heat treated at different temperatures, and diamond/copper (Cu) composites were fabricated by using a pressureless infiltration method afterwards. The influences of heat treatment on the microstructure and composition of tungsten based coating surface and diamond/copper composites were analyzed. Notable differences were found in the microstructure with heating temperatures. Moreover, the tungsten based coating surface contained large quantities of oxidized tungsten, and the phase composition of the coatings varied within the range of tungsten-W2C-WC as the heat treatment temperature increased. The fracture surface morphologies in the copper matrix composites reinforced with diamond particles with coatings were identically characterized with the presence of ductile fracture of matrix accompanied by dissociation of diamond particles from the matrix. The thermal conductivity (TC) and gas tightness behaviors of the diamond/copper composites were also explored. A maximum TC of 768 Wm -1 K -1 and a fine gas tightness of 2.5×10-10 Pam 3 /s were obtained with reinforcement of tungsten-coated diamond particles treated at 800 ℃. The value of the interface thermal resistance between copper and diamond particles was also estimated and specifically discussed.

Effects of Chromium Carbide Coatings on Microstructure and Thermal Conductivity of Mg/Diamond Composites Prepared by Squeeze Casting

“…Numerous efforts have been devoted to improving the thermal conductivity of metal matrix composites; however, there is a paucity of research literature on magnesium-based composites. The commonly used coating methods for diamond surfaces include the molten salt method, vacuum micro-evaporation, chemical vapor deposition, magnetron sputtering, and sol-gel [24,25]. The molten salt method is one of the most commonly used coating methods due to its low cost.…”

Effect of Diamond Surface Pretreatment and Content on the Microstructure and Mechanical and Oxidation Behaviour of NiAl/Fe-Based Alloys

“…Scholars found that tungsten layers can be coated on diamond by a microvacuum evaporation diffusion method and then, diamond/copper composites can be prepared by vacuum pressureless infiltration. The resulting full uniform plating layer on the diamond/copper interface has high thermal conductivity [ 16 ].…”

“…It has not only high hardness and chemical stability but also excellent thermal conductivity (600-2000 W/m•K) and thermal stability, so it is now widely used for polishing, as a particle reinforcement and as a composite coating, for example [13][14][15]. The interface bonding strength between the matrix and diamond may be primarily due to mechanical mixing without a transition layer [16]. The interface between the Fe matrix and diamond particles is the major determinant of the Fe/diamond composite properties.…”

“…Therefore, pretreatment of the diamond powders is very important for ensuring adhesion between the diamond and matrix. In recent years, research has focused on surface pretreatments of the diamond to solve such problems [16][17][18]. Scholars found that tungsten layers can be coated on diamond by a microvacuum evaporation diffusion method and then, diamond/copper composites can be prepared by vacuum pressureless infiltration.…”

Review of cooling solutions for compact electronic devices

“…For example, diamond, which is a highly ordered crystalline solid, has the highest known thermal conductivity 2300 W (m K) -1 at room temperature. Composite materials made of diamond and copper with the thermal conductivity of 768 W (m K) -1 can be prepared by pressureless infiltration(Jia et al, 2019;Parashchuk, 2016). Despite their higher price, diamond/copper heat sinks are used in the cooling of sensitive electronic components such as power diode lasers because of the excellent thermal conductivity of diamond.…”