人造金刚石颗粒的镀镍工艺(英文)

Nickel plating of synthetic diamond particles

介绍了一种容积约为200mL的微型密闭滚筒的设计,其主要包括以下部件：丙烯酸管（长60mm、外经76mm、壁厚3mm）及两侧圆盘,不锈钢中轴,不锈钢阴极棒、镍阳极盘,特富龙套筒、螺帽和滑轮。采用该滚筒对2g化学镀镍后的人造金刚石颗粒（粒径为100~250μm）进行滚镀镍。化学镀镍前,人造金刚石颗粒按如下步骤前处理：先用含1%氢氟酸的10%硝酸溶液处理5min,然后采用含10g/L氯化亚锡和40mL/L盐酸的溶液敏化120s,再用含0.5g/L氯化钯和10mL/L盐酸的溶液活化120s。化学镀镍的溶液组成及工艺条件如下：硫酸镍25g/L,柠檬酸钠30g/L,次磷酸钠25g/L,硝酸铅1mg/L,温度85°C,pH4.5,连续缓慢搅拌,时间10min。滚镀采用瓦特镀镍液,在转速12r/min下先后用30mA和50mA电流各镀10min。经上述处理后,人造金刚石颗粒被镍镀层完全覆盖,可用于制造镶刃工具。

The design of a closed-type mini barrel of about 200 mL capacity was introduced. It mainly consists of one acrylic tube（length 60 mm,external diameter 76 mm,and wall thickness 3 mm） and two side acrylic discs,stainless steel central shaft and cathode rods,nickel anode disc,as well as Teflon sleeves,nut and pulley. Two grams of electroless nickel plated synthetic diamond particles of 100-250 μm in diameter were plated with nickel by using the barrel. Prior to electroless nickel plating,the synthetic diamond particles were pretreated by the following steps：（1） pickling with 10% nitric acid and 1% hydrofluoric acid for 5 min;（2） sensitizing with stannous chloride 10 g/L and hydrochloric acid 40 mL/L for 120 s;and（3） activating with palladium chloride 0.5 g/L and hydrochloric acid 10 mL/L for 120 s. The bath composition and operation conditions of electroless nickel plating are as follows：nickel sulfate 25 g/L,trisodium citrate 30 g/L,sodium hypophosphite 25 g/L,lead nitrate 1 mg/L,temperature 85 °C,pH 4,continuous mild agitation,and time 10 min. Barrel plating was carried out with a Watts bath under a rotation speed of 12 r/min by successively applying current 30 mA and 50 mA for 10 min individually. The synthetic diamond particles were completely covered with nickel coating after the above treatments,being able to be used in the fabrication of tipped tools.