CVD and The Heat Treatment of CVD-Coated Tool Steels
PAN Xiao-hua1, ZHU Zu-chang2
(1. H.E.F. Shanghai, Co., Ltd., Shanghai 200030, China; 
2.Shanghai University of Engineering Science, Shanghai 201620, China )

        Abstract: Some new typical materials with single layer or multiplayer structure of the grade of micrometer or nanometer can be made by means of vapor phase deposition technique. It is the most important and interesting to coat mechanical parts and tools with the hard deposited films. At present, coating the carbide is produced with CVD methods and coating the HSS and high alloy steels with PVD and PECVD methods. In this paper the author’s index out that those tool steels, with high hardenability, secondary hardening behavior and austenitizing temperature near CVD temperature, can be CVD-coated in order to gain the excellent properties of the superficial deposited layer but also the substrate. As a matter of course, those steels must be treated through the strengthening heat treatment in vacuum or protective atmosphere before and after CVD process.
        Keyword: CVD; chemical vapor deposition; tool steel; mould; heat treatment; microstructure

1.   CVD涂层技术概述
        近30多年来,气相沉积是材料表面改性中获得迅速发展和应用广泛的表面涂层技术。气相沉积是利用气相中发生的物理、化学过程，在工件表面沉积固态膜层的一种工艺方法。应用气相沉积可以获得微米级或纳米级的单层或多层的新颖材料，它们是具有特殊的物理性能或化学性能或力学性能的与基材具有不同结构的新材料。沉积的固态膜层主要有装饰功能薄膜、物理功能薄膜（如光学膜、微电子膜、光电子膜和信息存储膜等）、机械功能薄膜（如高强度高硬度膜、自润滑膜、耐磨损和耐腐蚀膜等）以及特殊功能薄膜（如高温下耐磨损和透光的金刚石膜）等。被沉积工件材料可以是金属、硬质合金、陶瓷、聚合物和玻璃等。涂覆的薄膜主要有金属膜、合金膜、氧化物膜、氮化物膜和碳化物膜等^[1]。