화학공학소재연구정보센터
Applied Surface Science, Vol.356, 429-437, 2015
Temperature dependence of W metallic coatings synthesized by double glow plasma surface alloying technology on CVD diamond films
W metallic coatings were synthesized on free-standing chemical vapor deposition (CVD) diamond films using double glow plasma surface alloying (DGPSA) technology. The influence of varying metalizing temperatures on the microstructures, phase composition and adhesion of the W metallic coatings were investigated. Likewise, the effectiveness of the W metallic coatings was preliminary evaluated via examining the shear strength of the brazing joints between W-metalized diamond films and commercial cemented carbide (WC-Co) inserts. The results showed that continuous and compact W metallic coatings were formed on the diamond films in the temperature range of 750-800 degrees C, while cracks or cavities presented at the W/diamond interface at 700 degrees C, 850 degrees C and 900 degrees C. Inter-diffusion of W and C atoms preformed, and WC and W2C were formed at the W/diamond interfaces at all temperatures except 700 degrees C, at which only W2C was formed. Moreover, etched cavities appeared at the W/diamond interface when the temperature exceeded 850 degrees C. The critical loads for coating delamination, as measured with the scratch test, increased as the temperature rose from 700 degrees C to 800 degrees C, while decreased with further increasing temperature. The maximum load was obtained at 800 degrees C with a value of 17.1 N. Besides, the shear strength of the brazing joints depicted the similar trend with the critical load. The highest shear strength (249 MPa) was also obtained at 800 degrees C. (C) 2015 Elsevier B.V. All rights reserved.