Contents lists available at ScienceDirect Journal of Materials Processing Tech. journal homepage: www.elsevier.com/locate/jmatprotec Study on electroless composite plating for an NieP bond micro diamond wheel Tianfeng Zhou a, *, Yupeng He b , Qian Yu b , Zhiqiang Liang a , Shidi Li b , Xiaohua Liu b , Xiaobin Dong b , Xibin Wang a a Key Laboratory of Fundamental Science for Advanced Machining, Beijing Institute of Technology, No. 5 Zhongguancun South Street, Haidian District, Beijing, 100081, PR China b School of Mechanical Engineering, Beijing Institute of Technology, No. 5 Zhongguancun South Street, Haidian District, Beijing, 100081, PR China ARTICLE INFO Associate Editor: Yip-Wah Chung Keywords: Micro diamond wheel Electroless composite plating Diamond particles Ni-P alloy Microgrooves grinding ABSTRACT In this paper, nickel phosphorous diamond (Ni-P-D) composite plating is introduced as a new method to fabricate a micro diamond wheel with a diameter of φ450 μm. In the fabrication process, the steel substrate (SKD-11) is first ground to a ball end shape with a radius of 200 μm. Nickel phosphorous (Ni-P) and micro diamond particles with an average grain size of 3.5 μm are then electrolessly plated on the steel substrate tip, with a final plating thickness of approximately 25 μm. Parameters of the Ni-P-D plating conditions, including substrate rotation, stirring speed, and diamond grain density are then investigated. The topography of the micro wheel shows that diamond grains as the reinforced phase are embedded omnidirectionally and uniformly in the Ni-P plating along both the surface direction and the thickness direction. Energy dispersive spectrometer (EDS) results indicate that the ratio of diamond grains is approximately 27 wt%, and the Ni-P plating layer is an alloy in the amorphous state. Once fabricated, the micro diamond wheel performance is tested by grinding microgrooves on single crystalline silicon. The machined microgroove has a surface roughness of Ra 26 nm without obvious cracks. Micro tool wear after grinding proves that the bonding strength between diamond grains and Ni-P alloy, as well as the adhering strength between the Ni-P plating and steel substrate, are strong enough to meet the require- ments of the micro grinding wheel. 1. Introduction The increasing demand for the manufacturing of microstructures on high-hardness materials such as cemented carbide, silicon carbide, and silicon, requires a superabrasive grinding wheel of a small size. Aurich et al. (2003) presented the concept of superabrasive electroplated grinding wheels based on defined grain structures. Lu et al. (2012) introduced a new kind of the superabrasive grinding wheel designed based on the phyllotaxis theory of biology. Cubic boron nitride (CBN) and diamond were widely used to fabricate superabrasive grinding wheels by electroplating and brazing for enhancing the ability to ma- chine high-hardness materials, according to Ding et al. (2017). The strength and the impact resistance of a grinding wheel are mainly de- termined by the bonding agent. According to Anand Ronald et al. (2009), metal bonds are predominantly employed in the fabrication of superabrasive grinding wheels due to their excellent formability and high strength compared with resin bonds and vitrified bonds. Traditional grinding wheel manufacturing methods using powder me- tallurgy technology (Miura-Fujiwara et al., 2012) are not suitable for micro grinding wheels due to low mold accuracy and complicated op- eration. Instead, electro plating and electroless plating methods can be used to fabricate metal bond superabrasive micro grinding wheels. Both techniques are achieved by preparing one layer of composite plating composed of superabrasives and metal bond on a micro substrate. The electro plating method has been widely used to fabricate micro grinding wheels due to its low cost. Onikura et al. (2009) conducted the fabri- cation of micro cylindrical diamond grinding wheels with diameters from 100 to 500 μm by electroplating of diamond grits in a Watts bath. However, only a single layer of abrasives can be embedded in the metal bond with high residual stress, resulting in a short life of the grinding wheel. The uniformity of abrasives on the grinding wheel is also limited by the distribution of the current, which may reduce the shape accuracy of the micro wheel. Jappes et al. (2005) found that electroless plating has a wide range of commercial applications mainly due to good https://doi.org/10.1016/j.jmatprotec.2019.116561 Received 12 June 2019; Received in revised form 7 December 2019; Accepted 15 December 2019 ⁎ Corresponding author at: Key Laboratory of Fundamental Science for Advanced Machining, Beijing Institute of Technology, No. 5 Zhongguancun South Street, Haidian District, Beijing, 100081, PR China. E-mail address: zhoutf@bit.edu.cn (T. Zhou). Journal of Materials Processing Tech. 279 (2020) 116561 Available online 18 December 2019 0924-0136/ © 2019 Elsevier B.V. All rights reserved. T